A suggestion from a streamer was the following :

Based on your current upgrade of cranes amount, a building would show you the ideal input speed of each module to achieve current maximum ideal output.

For example the first building ( grey core ) at the beginning with your 4 cranes would show 15/m for module 1 and 30/m for module 2, because that is the best you can achieve (for a nice number at least, you could technically reach higher with a 4th crane ans sushi belts but that would be unnecessary imo)

If you upgrade to 6 cranes, then it would show 30/m for module 1 and 60/m for module 2 because that is now achievable.

This would make it easier to understand how many modules/min the building is expecting for its etimated output/min.