I really like how in progressing through the game you get boosts to your machines. For instance Assemblers start at 15/min then 30, then 60 (That's as far as I am rn so don't know if it goes further). However, in building parts to maximize output of final piece its almost certain that I will say be running 30/min into each Assembler input to get 30/min out. But the assembler still says 60/min in on each input and 60/min out and the efficiency view shows yellow not green which is so unsatisfying. I can try to keep track myself or use a counter as a reminder. But it would be monstrously beneficial to set that assembler to only 30/min.

Worded Nicely: I would love a choice to set any machine to a lower efficiency or "speed". Say once I've unlocked 60/min Assembler, I want to set some Assemblers to 30/min so I get nice green in my Efficiency