When I want to make 1 assembler to produce gears, I have to either know that a single assembler produces 60 gears, or just add a value of 1 or 90 or 900, add gear recipe, then adjust until it matches. Or I can hard limit the gear maker, and then match the number, then unlock it. Its always just a hassle though.
I would like the "Amount per belt" to also have an "Amount per recipe" type thing that lets you chose any recipe+assembler+module loadout, and a number, which it then tells you how many are produced and enters it for you. So I just say, Iron gear, my recipe, grey assembler(my default), and it gives me 60 instantly, and also adds that recipe to the board, unless it was already there.

Also, sometimes I want to double or triple or cut by 96% or other mathy thing and wish it let me stick equations in that box and have it solved. Its easy to half 90, and half 45, but then you get into fractions, and worse when in mods you already have weird and fractional numbers I don't have memorizing adjusting furthers gets to be a pain. Especially once productivity modules get involved and break what were nice clean and already memorized ratios.

Thanks for the suggestions. Calculating by machine count isn't quite trivial, since you don't know which machine or even which recipe will be used when you enter the item, so it can't be translated to an amount at that point, only after the recipe is all set up. I do have an idea for how to do this, but it'll need some more infrastructure work to be done beforehand, so I don't know when it'll happen.

The second one is something I wanted to do for quite a while, but it simply wasn't high priority enough at any point. Same as above, I'm not sure when I'll get to it, but I do want to do it.