Lance: Very much like your workmanship over the factories there.
Only suggestion would be to use a non flammable back plane.
My fear would be that if a loose connection developed, the heat could lead to a larger issue.
Many years ago, I caught some guff at work from the more experienced engineers when I built one of my first inverter cabinets in a 3'w x 6't metal cabinet with a plywood back plane.
Funny thing is, the managers didn't know better and put a large picture of the cabinet interior on display in one of our conference rooms. We all got a chuckle whenever we would go in there for meetings.
That picture lives in my garage now.
Something like this:
https://www.mcmaster.com/electrical-grade-fiberglass-(gpo3)/ might be more appropriate and is short money for a 12"x12" x1/4" piece.
As usual your energy and ingenuity amaze me.

And thanks for the heads up on factory wiring error. I will certainly be checking my PC for that un-fused conductor.
Regards.