Ratios of buildings and the components they need

As someone who really enjoys perfecting ratios of source components in factory automation games, it's frustrating to figure out how many units a building will produce. Primarily thinking of the larger buildings that make the grey gears/robots/paint etc.

Also I generally try to have full belts just making a full belt of the first two components for the gears takes more extractors/smelters than the starting corner can provide. Perhaps the tech tree is meant to resolve that (better extractors/etc). But a little mentally frustrating in trying to optimize early.