First thing you need to figure out: Where are you going to get the matching connector bodies? Pins and seals are less of a problem but you still need to identify a source.
Next thing: How do you plan to color-code the wires? First Guess--you're not. Or at least, they'd be minimally color coded. There's a few colors of wire available, plus paint pens for stripes. I worked for a company that put numbers onto white wires, you'd pull the wire through this machine and it would print [circuit] 452 or 143 or whatever, every few inches, all along the wire. So there'd be five, twenty, thirty white wires in a bundle, but they'd each be identifiable based on the circuit number they corresponded to. Your harnesses would be short--maybe a Dymo lablemaker with a color code wording printed on a label you stick on each wire. Or...like I said...just don't worry about it. As long as each wire is correctly assembled into the proper hole in the plastic connector body, it may not matter.
A guy in his basement or garage can do wondrous stuff that functions well...but it generally doesn't look like an OEM product.
