You don't have to be too picky about your wiring, I've done up an entire prototype with 24-gauge phone jack wire before and it worked like a charm. 24-gauge is however harder to deal with and a little harder to get to look neat. I'd say the proper gauge would be between 18-22, I believe I did my cabinet with 18 gauge and it worked great. If your quick disconnect has too much room when you put the wire into the part to crimp, one trick my dad taught me was to double up the wire so when you put it in, your essentially putting in twice as much wire. If your worried about how clean it looks, theres a few key things to making your wiring look clean I've learned so far:
-repitition
-zip ties!!
-distinct color between controllers / sections
-make all the wires go to one central big zip tied wire, and bring that around the edges
the next project I do I think I'm gonna basically make it so that I can really practice up on making my wiring super neat. I'll probably go the Sirpoonga way and buy these like fish net things you can put around the cables, then clamp em to the sides of the control panel, and lay them out all color coded and nice. That extra 30 minutes of work will make the insides look SOOo much freakin nicer, so if you ever need to open it up you'll be like "Holy crap, I did this thing??"