(of course, to produce those 10 belts of circuits the input will be 90 belts of plates (58 copper+32 iron) and the steel and gear will require 24+6 belts of iron, so the preprocessing part will be pretty massive compared to the actual bus. To get 800 spm you'll need something like 8 belts of iron, 6 belts of copper, 5 belts of green, 4 belts of red, 1 belt of blue 4 belts of steel and 3 belts of gears. If you produce circuits, steel (& gears) before the 'main bus' part, you can make do with pretty small numbers. So in short, if you produce your circuits (and steel & gears) on the main bus, you'll need massive iron and copper which will be mostly empty after the circuit production. This is a nice visualization of the same process: The rest of science+rocket production consumed only 6 belts. Out of 64 belts of copper, 58 were used for circuits (48 for green, 10 more for red). All other users were 9 belts (and engines produced steel on site because it was more convenient, so the actual numbers are even more skewed) I always opt for a robot based base, but without the 'spine' of the Main Bus the base easily becomes. Sure it is a step up from random spaghetti, but to me it doesn't scale well and doesn't lend it self easily to robotic transition. In my base, out of 69 belts of iron, 32 were used for green circuits, 24 for steel, and 6 more for gears. It seems that using a Main Bus or Central Bus is all the rave these days. What is important to realize is that iron and copper are mostly needed for circuits and steel. I did a belts-only no-modules 800spm base here: I love using helmod to do all calculations in-game, but of course a spreadsheet is fine as well. I'm not a fan of linear buses, but I would urge you to plan out a production target and design according to that.