The corner was by far the hardest part of this project, both because it had more rot in it and because the bend is too tight to do in the shrinker. I experimented a bit and finally took a piece of 1/2" wide flat sheetmetal and bent it around the edge and then welded a back to it, to form the corner piece. I need to buy a different burr for my die grinder so I can smooth out the welds in these, but other than some finish grinding I did get this side done. The other side is in slightly better shape, and I hope it'll go much quicker.
I've decided to try to use the 88 Chevy seatbelts too to go with the seat, and in order to do so I'm going to have to remove the bulkhead that used to be between the gas tank and the under seat toolbox. Because I feel this is a structural piece due to how it ties both of the B pillars into the floor directly above the body mounts, I've picked up some 1x2 rectangle tubing to build a new brace under the floor to tie in both original supports. Hopefully this will keep the back of the cab from ever sagging....