Sorry I can't help, but have you contacted Shell Valley?
Midstates and Shell Valley merged a few years ago, they may be able to help even if the wiring harness is not their product. I visited the shop and they had a bunch of very competent guys in there...the one who was responsible for narrowing their Ford 9" rear ends wore a white lab coat as he did his measurements
Good luck...electrical issues can be the biggest bugaboo regarding these builds!
Cheers!
Dugly
