Thank you for the offer. I think what happened was that I slowed down the switching too much, overcompensating for an earlier design that switched field current at way too high a frequency and ran the field coil like it was a boost converter. I basically copied the Mopar design for my latest revision with an adjustment circuit added but had to guess at capacitor values, and I think I guessed an order of magnitude or so too high.
And I may have a line on a way to make an adapter to stock Mopar wiring as well - I ordered some contacts that may fit along with new capacitors yestereday.