Would you consider adding a smaller factory? I had been messing around in Factorio, and I realized that I didn't have enough space to put in a 4x4 balancer. I have my own solution to fix it, but I think it'd be worth while to have an even smaller factory building that just is good for quick balancers, or other stuff like that. A "Factory Shed" of sorts.

Belt connections aren't that great for UPS, so it is generally not a good idea to use factory buildings as balancers.

I would also want smaller factories (smaller footprint and smaller number of connections).
UPS is not a concern.

for the balansing use loaders + large storage

for the balansing use loaders + large storage

I am using x8 stacked items on belts. When I feed a belt into large factory, first i put small factory inside to unstack 1 belt to 8 belts and balance them inside this small factory, which then feeds manufacturing factories. Currently it's overkill, as i am only using 9 i/o ports (1 stacked in + 8 unstacked out) instead of 16 and maybe 1/2 of the space of small factory.

here is the example on the inside of copper mfg factory. It feeds in 2x stacked belts of copper and spits out 4x stacked cables:
https://imgur.com/A8AxH7U

this is effectively 16x worth of red belts worth of cable producted inside one large factory and i even have space left which i could've used if i had type factories

and this is the inside of 8x to 1x stacker
https://imgur.com/3o1pJ9l

as you see it's mostly unused.
for my play style i need either 18 or more i/o ports in a small factory or smaller tiny factory with no less then 9 i/o ports

here's another use case:
https://imgur.com/FyBLT2o

this is the input unstacker + router factory for coke production. it takes in stacked wood and coal, unstacks them and combines into belts.
this is how the outside of that router looks:
https://imgur.com/hmcuzR0

anyway, it makes sense to have more flexibility for factory sizes and i/o options i think. it's easy to implement i would imagine and can be balanced into the same tiers in terms of research costs as it's mostly a QoL thing

On a ups note, i kinda don't care because of my home PC specs and then if i hit a limit, i will run headless on a server or even split into instances and connect via clustorio or something. I have spare dedicated servers :)

http://joxi.ru/82QE8MKI994db2 - 1 in --> 8 out or 8in/1out
http://joxi.ru/YmEGZYMCMMLjjA - Warehousing +miniloader+belt sorter
https://mods.factorio.com/mod/belt-balancer - Any in/any out

thanks for the designs indeed.

however, i'm am also stacking/unstacking, it's not about balancing.
once you add unstacker on to each out lane, it starts to take more space and once again makes sense to put inside small factory for space/cleanness reasons.

https://mods.factorio.com/mod/deadlock-beltboxes-loaders
i am using these as loaders/stackers
also using belt sorter, but it crashes on me randomly in sorting GUI, so i use it sparingly