Preamble:
I played this mod with space age, quality, rails and of course Krastorio 2 spaced out (and all its prerequesites)
(At time of writing (73 hours in) I have automated the 3 planetary science, however I need to rely on getting to those planets to actually get the plants and specialized ores)

Playstyle:
-I dont like excessively using bots, I will use it if there is not real other option, but I still want small factorie areas which produce and handle specific ressources and sciences, and I like using belts when possible.
-I like self sufficiency and ressource efficiency, obviously this is much more relevant with dimensional warp since it can sometimes be quite a bit of time between any specific ressource patch so thats nice.

Start (Red Science):
-Early game is largely unchainged from non krastorio 2 playthrough (at least I think).
-Red (And all other) science is a bit more complicated and the platform is obviusly tiny but I just build a bit outside the platform and thats fine.

First Layers (No electric distribution)
-The teleporter do transfer power between layers, so I used and set up basic automation before I was able to get all the green science for the electrical distribution inside the platforms. Krastorio also has wind turbines which while obviously extremely space inefficient are great to get a little bit of electricity.
-Green houses produce wood slowly but infinitly as long as you give them water, which is usually easily and infinitly accessable on all nauvis variants.

Green Science
-With electric distribution on the platforms done I focused on all the red green platform expansions as space was incredebly tight.
-I also used greenhouses to produce wood as fuel for my boilers and furnace, while not perfect this means I needed vastly vastly less coal and setting up miners or hoping to get a coal plant was something I wanted to avoid as much as possible. Notable steal requires coke which requires coal specifically (or carbon)
-The on planet platform was basically only used for defense with gun turrents and yellow ammo, yellow ammon in krastorio deals 10 damage instead of 5 and simple gun turrets are holding fine with no damage to my walls even right now 60 minutes on each planet with big biters. The damage upgrade increase both turret damage and ammo damage multiplying gun turrets to 152 damage per shot in the current late game, making them sufficienct for anything except large gleba stompers (before your reduced gleba evolution I think)
-I then also rushed the basic harvester platform to make mining way way easier to set up.

Blue Science:
-Blue science is where the cost complexity really starts, for example it actualyl needs sand from stone with specialized intermediares and so on. Setting up blue science was a huge mess and I barely had any space left.
-I also used efficiency modules in everything cause -80% electricity is absolutly crazy.
-I did not use the beacon, with a permanent -10 mw power cost and an area which only covers the very center of my factory at the time it consumed more electricty than the entire rest of my base combined (Even right now in the late game with a preety large factory I still only use around 33 mw so I still havent got it. I also didnt know that it allows for producitivy modules since normally beacons dont accept productivity beacons, but even then the electricity cost is absoultly insane. I did unlock it once and then reload a save cause. It also barely covered a tiny area in the center of my factory where I have to put all my belts for transferring items anyway putting say labs or rocket platforms in there would be nightmarish belt routing ontop of the already super tight space.
-Since evolution seemed to increase with every planet completed I tried to stay on each planet as long as possible, ammo is also quite cheap with krastorio 2 so that was never a problem. Combined with me running on greenhouses for electricity combined with efficiency modules.

Stuck on produstria size:
-After blue science the next size upgrade requires space science and productivity science in LARGE quantities so that took a really long time with the insanely limited space available. Notable productivity science also require uranium which I build AROUND the harvester platform area in that jusst cause I really didnt have space.
-ADDITIONALLY the next size upgrade ALSO requires utiltiy science since it requries the Warp Generator 5 technology which requires i, thats 3 new sciences before then next size upgrade so ye took a long time.
-I set up a small hand fed/few bots fed military science setup, mostly cause I was scared of larger biters killing me, but also cause it unlocks tons of utility stuff.
-Krastorio also adds an advanced lab which has 80% science consumption as an inbetween from the normal lab to the bio lab which is very nice.
-Since I was desperate for more area I set up rockets, since that could possibly help save area by producing iron or more complicated iron things and then sending them down from orbit. Space science is of course also necessary for logistic bots, a variety of other usefull techs and the insanely important next produstria size upgrade.

SPACE TIME:
-Once I had setup space (notably rocket fuel is a bit different in krastorio and blue circuits require the new ore which needs specialized chemical mining etc), I tried to expand the platform to produce more iron per second from it. OF course thats not actually how it works and factorio spawns the same amount of asteroids for stationary platforms regardless of size. EVENTUALLY I figured that out.
-Since space science is effectivly free I researched fulgora and vulcans, as the electro plant and the foundry woudl be insanely helpful for savign space and ressources.
-I then switched my smetling setup to use foundry lava instead of just ores (still using ores when running out of lava) since large steel tanks are 5x5 and can store 200k lava you can preety reasonable tank up on lava and not worry about mining iron. It also produces a tiny amount of stone, It also helps ease my miners since with krastorio 2 new ores and calcite and scrap and coal for plastik and stone, ore lanes were hard to get
-I then build a bunch of asteroid harvesters to produce carbon and iron
-I set up a tiny setup for rarity 3 tier 2 productivity modules to make rockets slightly less painful and slow.
-Eventually I set up a 1 machine bot fed setup for productivity and utility science, they were slow and it took a while for a nauvis plant to show up when I needed the uranium, but with everything there was literalyl absolutly no space.
-The Heavy oil from fulgor was invaluable to make my one oil refinery keep up with my base

Odd sciences:
-With productivty and utlity and space science more produstria size was finally slow but achievable, since I was still frequently running out of various ressources I focused on getting more space platforms into space. Also I just really not having to worry about a ressource running out.
-After a while the space platforms produced enough iron to shut off the foundry producing iron, making the lava supplies last longer.(6 iron carbon platforms at time of writing)
-After getting asteroid chunk conversion with vulcanus science I also set up 2 carbon only platform to produce more carbon, and then send that carbon down to the furnace area to make steel with instead of using coal.
-I was very scared of gleba and so I tried to get a lot of military. I also automated some terrible fulgora science for the lightning turret just in case.
-I also made a space platform to provide red belts, undergrounds, loaders, engines and pipes to save on the space needed to build a mall. (I really like that one)

Gleba Time:
-Gleba went fine, I collected fruits by hand and warped away with only 30 or so of my turrets destroyed, I also set up flamethrower turret in addition to the gun turrets to be used on gleba stompers only. (Oil is limited, ammo aka iron is infinite)
-I rushed the bio lab cause 50% science cost is obviously crazy good, even with the previuosly lab already proving 20%, also 4 module slots.
-I also set up terrible bot automation for bio and fulgora science cause those are really comlpicated and a nightmare to route with belts in the still quite limited space.
-After gleba I redesigned my electria platform to turn wood and carbon into coke down there, then fueling the boilers with coke instead, additionally Krastorio also allows you to turn steam and coke into a small amount of oil so obviously I set that up, cause I want more ressources accessable.
-This meant I could reserach the advanced asteroid processing for more space accessable ressources.

EVEN MORE SPACE (current stand at time of writing):
-In general with the more planets unlocked there are a lot of useless planets, gleba but there is only one fruit is basically useless, fulgora has 2 variants which just dont have any scrap deposits. Various nauvis setups only provide some of the ores I need. Early game getting the no biter planets was nice, but now its mostly just nothing. I would REALLY like any way to designate which planet i want to go to or manipulate the odds in some way. I can only image this getting harder when I eventually get to aquillo.
-Since after each planet evolution increases I like to actualyl run out the time on each planet, this is also part of the reason why I wanted to produce so much stuff infinitly through space or similar. Its probably just something I really enjoy though.
-Coal and pretroliume for plastik is currently one of the things which runs out the most, last fulgora was a while ago and the coke to oil production is ok but not great. Right now I am investing into more coal platforms to get that too. (Producing plastik in space directly is horribly inefficient)
-I tried building one platform in space which produces rocket fuel directly but thats horribly ineffective and not viable.
-Anyway with the advanced asteroid processing I build steel and copper combined platforms with foundries in space, further easing my large copper demand and also saving space and fuel on the steel production which with factorissimo needed coke and wood otherwise.
-Right now I actually have a large amount of space in my furnace area since with the loaders and It can only really do the basics like producing copper plates, sand, and similar while everything else needs so many intermediaries and half processing steps that it kinda need to be on produstria or in space to have access to the sub ressources.

Most notable thigns:
-Defense is a bit too easy I am still using only gun turrets and yellow ammo and its 10+142 damage per shot, 30 shots per ammo item, 12 shots per second per turret. Obviously I did the gun turret research and I am only on dimension 123 due to using the full time, but it still feels a little too powerful.
-Krastorio and space age make it so I need a lot more planet specific ressources, I mitigated this by getting ressources in alternative ways but since planets are random and many of the variants dont have specific ressources, getting a specific ressource can take a really long time, it would be nice If I could reserach or feed or do something to say get a 50% chance to get a specific planet each warp, just something to change the odds. I havent seen scrap deposits in many many hours.
-The jump from produstria size tech needing green red and blue science to the very next upgrade needing space science AND production science AND utility sciene was a bit too large, I recommend moving at least one produstria size upgrade down to only requiring one new science instead of 3 new in one step.
-The beacon needs an on off switch and the research should tell people that it can hold productivity modules, I had no idea it could do that, most players will try the beacon early and heavily regret doing so, most likely needing a reload, then never touch it again since they have no idea how good it scales if it does, or that it can do productivity, etc. I think its probably even very good since apparently it has 2x module transfer efficiency too, but I certainly didnt want to try it and it preety much strictly require nuclear power for any use and it does have huge anti synergy with belt based factories. For my own playstyle I would much rather have one which is more expensive to reserach and has less module slots and module transfer efficiency, but in return always covers the left down corner of the full factory and requires way way less electricity, other costs such as needing a constant supply of iron gears would also be fine for. But of course thats just me specific so just the on off and the reserach info probably solved this problem for most people.

PS: I just got my first infested nauvis and I mean thats very fun, good work(this is not a jab I really like planets which feel different), however with 33% starting evo I lost only 2 gun turrets thanks to their rediculous damage output, I dont have any turrets fighting except gun turrets so even with my 3 thick walls this felt a little too easy.

For my test play with K2SO, I play a combo of AAI Industry + K2SO, so clearly, to fuel boilers it's far easier (due to the fuel recipe early game that has increased efficiency when converting any fuel to this fuel).

Early game

Red, green and blue science are, imho, "easy" to automate (my K2SO run has only unlocked drones / rocket silo so far). It requires spaghetti, but it's doable.
For wood, as only green circuits and coke are using it, I only gather it by hand (like 10-20k in chests at once) and refill it manually (less a pain / less space required than greenhouses).

Mall

My best advice would be to be able to setup a basic smart mall: you setup in a constant combinator what you want to produce, and then you compare your logistic network with what you need, and send a random signal (with the new combinator) to an assembler to build it.
With liquids it's also possible, but you want something to empty the pipes quickly. Examples: https://imgur.com/a/ywbtMDw or https://imgur.com/a/SkWsk1V The main downside here is that your drones needs to have everything available, and be "quick" to provide items.

Gleba

Gleba is easier to defend with tesla towers (with 1 or 2 upgrades), but it costs energy, that's the only way I found to reliably defend against medium and big stompers...
I'm also not a big fan of the variation I did for gleba (except the no fruit, fertile and flooded), but having juste 3-4 variation felt poor (but actually, it's complicated to have more anyway when there's few resources).

Selecting a preferred planet for the warp

This is something I have in my TODO list already (for SA only, to be able to increase the odds for a specific planet).
I initially planned to add it earlier, but for some reason I didn't. Still planned in any case :)

K2SO turrets damage

K2SO turrets + ammo are really strong clearly, that's the reason I ended increasing the vanilla ammo from 10 to 20 shots per ammo, because vanilla felt expensive for "few bonus".
On the contrary, with K2SO, it feels like biters are just a joke, as you said.

Produstia size cost

Levels (letters are science colors, except for SA science, M=Metallurgic, A=Agricultural, E=Electromag, C=Cryo) :
- 1 = RG
- 2 = RG
- 3 = RGB
- 4 = PW <-- need generator lvl 5 (so actually requires every 6 first science, up to yellow/purple)
- 5 = PWM
- 6 = PWMGE
- 7 = PWMGEC

Actually, it's not really the Produstia size upgrade gap from lvl 3 to 4 that's "hard", it's the generator levels :
- 2 = R
- 3 = RG
- 4 = RGBm (m=military)
- 5 = RGBmPY <- this one hurts
- 6 = PYW

I think it would be better to have something like that for Generator levels:
- 4 = RGBm (no change)
- 5 = RGBmW (space, instead of PY)
- 6 = PYW (no change)

And change Produstia to have its level like that:
- 4 = W (like the other surface, except the warp platform)
- 5 = PWM (like currently already)

So Produstia level 4 provide room to add purple/yellow, while 5th level is unlocked with vulcanus, and generator levels 5 is easier to get, while lvl 6 (which would unlock then the tech to select the destination for example) would still require some investments.

Factory Beacon

Off switch doesn't seem to be possible (deactivating the entity doesn't stop its energy consumption), so to achieve this, it's more complicated than I thought.

True about the description for productivity modules. I'll add this to the description

Easy biters

You can add the following mods if you want more challenge (explosive biters are a pain, as their base have nuclear explosion, so for infested nauvis it sometimes wrecks the defense)
- Cold Biters
- Armoured Biters
- Explosive Biters
- Toxic Biters
- Fulgoran Enemies (Electric Flying Enemies)

Cold biters can generate a bit of lags if there are a lot of them (due to their "frost fog" when dying).
Fulgoran enemies are really strong (that's really one of the few I tried that are really a pain, almost more than pentapods)

I still need to check if rampant fixed would work, or if it requires some tweaks, as it would provide also increased difficulty.

Question about size

This is the current size increase (in tiles) from unlocking Produstia to its last upgrade: 0=20, 1=28, 2=38, 3=60, 4=80, 5=98, 6=122, 7=152
Do you feel like Produstia size should be bigger overall? Should I keep the same "end size" but provide better increase in the first levels and less at the end ?

edits: fixed a few typo

Nice feedback in any case, thanks :)

I think the final size is probably fine, especially with how much you can put into space in the late game, produstria lvl 4 is just a real bottleneck, like I have enough area now (Especially with dropping ressources from space platforms). Can't say for sure though since I havent finished the game yet.

Rebuilding produstria with all the belts over and over again has been a bit of a hassel, maybe some expansions could just expand the platform in one direction, just ideas though this might be unfixable.

i've integrated some of the discussion in the last change (mostly the description for beacon and produstia tech / size)