Bill, I'm going through your whole thread today trying to make sense of everything. Why did you not cut the Prius body to be narrower? I have a feeling you have a good answer for why not and I understand that the sections of steel under the rocker panels are structural. But maybe new structural metal (a sub frame) could have been welded further inward, either on top or underneath the floorpans..?
If there's any other advice for me, I'm all ears. I found a Prius that was wrecked in the rear and would be a perfect donor chassis+drivetrain.
P.S. The elecric Avanti is for sale again on Ebay
https://www.ebay.com/itm/1979-Avanti...d=292555698540