Relating to jath's message - the whole factory system really needs also an optional "multiplier" parameter for the transfers between factories/storages, in case two or more masters need items from a slave factory/storage.
Example: creating Black Advanced Armory. You need to create Grey Hull, color it to black. Easy as it is so far. But then you need to transfer the Black Hull to Black Standard Armor (in Factory1), which needs Nacht Capsules (6 of them). Next in line is Black Standard Armor into Black Advanced Armor (in Factory2), which in turn needs Nacht Ingots (in practise, one piece needs a total of 60 Nacht Capsules).
If I use the same source for both Factory1 and Factory2, problems can arise, since Black Std Armor only needs 6 Nacht Capsules, whereas Black Adv Armor needs 60 of them. In practise, even if I have an abundance of Nacht Capsules available in a storage box, my production line never creates enough of Nacht Capsules for the last phase to be efficient. I end up having loads of Black Std Armor and only a few of Nacht Ingots in my Advanced Factory, which means production of the Advanced Armor in this last phase is really slow.
What would solve this would be a possibility to specify that my Factory2 gets to take 10 times as many Nacht Capsules from the storage box as my Factory1.