As I mentioned, you are welcome to use my old floor which has the usable cage nuts (I could possibly cut them out at a later date), and like I mentioned, I saw the brace on ebay for sale so you might want to look for this. I didn't see the cage nuts welded to it, but that may be a good start.

It will be trouble getting the seat support out without damaging the rest of the floor. I think Brink's did the welding back then, LOL, but again, I have a vert with braces underneath that complicated the removal of these.