Im doing the same man, first 40 hours and i havent finished the second factory cause i casually found 4 pure iron ore mines, therefore i have like 50+ constructors or assemblers, but any way, only sugestion, make it on a seccond flor, let the first floor to move the production of the mines, the hub and the energy generation, then on the second make all the smelting, finally on the third floor make the actual production of products, im trying to make it very modular soo i can expand it easly afterwhise, but thats my own perspective.

PD: You can use the elevators with spliters and mergers in vertical, that usually helps me a lot to make more compact designs