Thank you for all those research, it's not easy to figure out all the correct ratios. I don't quite remember all the details, but at the time I tried to balance all the 3 main ressources (iron, copper and oil) so it's great to see it worked. I don't think I managed to make a factory that efficient and it may be quite tricky (but hopefully doable) to fit everything into the limit space of the game. If you manage to do it, send me a screenshot!