Hello. Thanks for the mod.
Interesting parallels with the post I created a week ago on reddit(https://www.reddit.com/r/factorio/comments/1n93fy2/mod_idea_for_some_rebalance_of_sa/).
I was already going to make such a mod myself, but I'm glad that someone did it for me.
I'm currently completing a mod that rebalances the cost of technology in a similar way.

Hello. Thanks for the mod.
Interesting parallels with the post I created a week ago on reddit(https://www.reddit.com/r/factorio/comments/1n93fy2/mod_idea_for_some_rebalance_of_sa/).
I was already going to make such a mod myself, but I'm glad that someone did it for me.
I'm currently completing a mod that rebalances the cost of technology in a similar way.

Specifically about this mod. I like 90% of the changes, they are noticeable, they will affect the gameplay, but they are not crazy, like in many similar mods. The only thing I don't quite agree with is these changes:

"Asteroid Chunks: Now have a stack size of 10 (from 1)."
What is the purpose of this change? I think the asteroid stack size in the game is very cool, it encourages using sushi belt instead of storing in the central building. I have not encountered the fact that asteroids are difficult/uninteresting to manipulate on the platform.

Quality rebalance:
You've reduced the quality bonuses at all levels. I don't quite understand why. I don't have any statistics, but it seems to me that not a very large number of players use the quality mechanic anyway. Why make it even less attractive?
I see a different problem with quality. The game is designed in all parts in such a way that it makes the following strategy the most effective. Throughout the game, you ignore quality, because up to a certain stage of the game it is more of a headache than an improvement. And in the late stage of the game, you start crafting legendary items ignoring all other quality levels. And this is a strange situation. That is, in the game, it seems like only normal and legendary quality remains.
And to fix this situation, I would add a bonus to uncommon and rare qualities. And even better (though I haven't looked yet to see if this can be done in the mod API) increase the chances of uncommon and rare qualities dropping, and decrease epic and legendary a little. So that the chances are not +10%, +10%, +10%. But let's say +20%, +10%, +5%. This will increase the value of average qualities, and this will be an incentive to make quality things in the middlegame.

Hey!
Regarding the chunks: I specifically don't like the promethium belt weaving to store chunks. It's a funny idea but gets old really quickly, especially because there's no other penalty for using belts. My promethium ship has 2 extra cargo bays and they aren't even needed. We already cannot use chests. I think this change will make the late game more interesting by enabling other ship designs. If you still want to use cursed belts you can do that.

Quality: Balancing quality is really really hard. You said it yourself: on the one hand you want to make it attractive (for casual players) on the other hand making it attractive (strong) kinda ruins the late game (in a way) for veteran players because it's so overpowered and makes factories so small and productive. The goal of this mod is to rebalance, not to change the way mechanics work, because that would mean that you have to relearn parts of the game because they are now totally different. The game should still work the same way as before just with a different balance. That's why I don't want to overhaul and change the way quality works.
I don't think players actually care about the numbers. I didn't know off the top of my head how much better a legendary item is. All I know is that legendary is vastly better and the best late game option. A +100% bonus is still crazy good.

Thanks for posting!

Agree with vwasdf about the quality: almost no reason to be bothered with anything but legendary, just grow up to space casino and get everything legendary and skip all other quality levels. I would also make the boost from uncommon significant comparing to normal, to push players towards quality shenanigans, and then every further step gives less benefits. That should make the growth more smoother.
Now the idea looks like "why should I make all that steps one by one, if I can reach end game with normal quality and then make one rather easy step right to legendary". Exactly what you, avadii, did in you Alpha Cygni series.
I think having a good boost from uncommon, players will be more willing to go through the additional troubles. And then they will not stop, even if benefits from the further step are smaller. Like infinite research cost - it grows exponentially but it doesn't stop from trying to get more and more.
There's a rumors that space casino possibility will be removed in 2.1, let's see how it change the situation. But in my opinion, it just makes jump from normal to legendary more complex, but it won't make players mess around the quality during all game.
Anyway, the mod looks great and interesting. Just think about it, probably it worth to make quality chances configurable? Not each of them, just the choice between two schemas: "equal" or "progressive" (or should we say "regressive"). Would be interesting to try both of them IRL.

I looked in the API and it allows to modify the chance of jumping between quality levels.
You could leave the bonus coefficients as you did, but change the drop rate as I suggested. Not a flat scale of +10%, +10%... But +20%, +10%, +5%...
That way, high-quality items won't be too powerful(as you want), but the drop rate for mid-quality items will increase(as it should be in base game IMO).
But of course this needs to be tested, these are just thoughts.

That's already the case isn't it?
To get the next level of quality you already get the added value of all modules which can reach up to 25% and even more depending on module slots, every level after that is 10%. So it's already the case that getting mid-quality items is very easy.

The purpose of this mod isn't to overhaul quality but to make factories larger again. To reach that goal the insane productivity and speed has to come way down. There's no other way other than nerfing the bonuses.

Hey AVADII. Regarding the promethian belt weaving (specially because there's no other penalty for using belts), there are a couple of mods that change the acceleration based on the platform's size/shape. Simpler Platform Drag makes it such that there's not a bonus/penalty for skinny/fat ships, while Space Age Overhaul puts more emphasis on each tile affecting acceleration (making the trade-off between lots of belts vs. faster ships a player choice). See data.raw["utility-constants"]["default"]["space_platform_acceleration_expression"] in the mods' respective data*.lua files for details of their implementations.

I personally find these more interesting as it gives the player the choice with gameplay consequences. Simply increasing the stack size doesn't have any positive or negative gameplay effect for design choices.