Some way of telling a slot to request a resource before the process needs it would be useful in fine-tuning the resource scheduling. Maybe some kind of belt sensor that fires whenever a car passes it?
you could always use the stockpiles for that
even with stockpiles a slot would request parts only when there is enough room at the internal stockpile.
So the ‘Fit Body’ and ‘Fit Engine’ slots need more components as they have room for.
But I agree, some slots would run much better with such a feature but I’m afraid researching the specializations and splitting up such slot into several specialized slots is more effective.
I agree with MaN1aC… in the end splitting up the slots would be more effective in those cases.