I got a bit further. I welded the pieces that capture the seat rail onto the seat adjuster. When I tack welded the pieces, I slipped a folded over piece of paper in between the slide and the bracket so the fit wouldn't be too tight. It turned out just great...not too loose and not too tight.
I took the pieces of square tubing that make the rear slide channels over to the milling machine and took one side off and cleaned them up a bit. I also made up a pattern for the outside seat guide using a modified version of the seat adjuster and made two pieces. The outside rail also gets captured by a bracket, but only on one side. I still have one scrap wing attach bracket that I can cut and use for that purpose.
