You’re absolutely right Paul. The latest posted diagram makes a lot more sense to me. I’ve posted a comment on the AeroElectric forum to solicit comments. I’ll share any pertinate ones here. I will say again though that there is no reason to isolate/insulate that forest of tabs from the firewall in our particular instances. It’s made to be mounted that way, hence the big through bolt is part of it. It actually happens to be part of an engineered strategy to help prevent ground loops. The way the wiring is shown in the second drawing is a fine way to wire the ground circuitry also.