I didn't go back through the other thread, but this is probably in there. It models a hinged diverter with (because of the vehicle proportions) a stinger upright at the end. The rigid floor resolves a lot of the iffyness. At the time I showed air scoops along the front edge for inflation. I'd consider tube and skin or double-walled inflatable, else fiberglass rods that store along the roof driprail.