... I found the EL 168 harnesses listed as being sold by Chev's of the 40's as well as Classic Parts. Doesn't appear to be much help as it only lists one #13 wire. Sorry

Yep - Those are the instructions I have. You can see why I was worried about this part of my project. I was hoping to have step-by-step instructions guiding me through all the wiring, but no so. Good news is I'm almost done with it. Need to get the headlights wired and installed and a couple small clean-up items. I'm feeling good.