I’m getting to the stage where I want ALL my manufacturable items to be produced in-house, but it is tricky with the way the current prioritization system works, (must be the closest source to the fitting assembly).
I suggest an option to turn off imports of specific items – windows, axles, etc. (Maybe a tickbox-like affair). (Also maybe add warnings if you turn off a tickbox, but there is no current X Manufacturing in the factory).
This way, positioning in the factory won’t be the end-all, preventing some very expensive moving of equipment, re-sorting of upgrades, etc. It would also allow for specialization in the factory – some players may want to segregate manufacturing toward one area of their building etc.
… to add to that possibility, it would be very cool to have different Resource Conveyor lines, (maybe 4 different colors? Red, Blue, Green, Yellow) – these lines would not interact/connect, and would mainly serve to pass over other lines. (I’m suggesting this idea from a conveyor traffic-management perspective).