Now that the “skeleton” is in place, I’m thinking this thing needs some skin. I picked up these 4’x8’ sheets of plywood at Home Depot. They cost a bit more than I feel like they should. Something like $25 a piece. But it’s about the only thing that will work for this. The other thing is it’s impossible to find a sheet that is perfectly flat. Makes them tough to cut in the extreme cases.
The prototype for this is easy: two clamps and a sheet