My solution was a bit more simple, but I also didn't want the tire standing up because it was in my line of sight and also going with 35s it hits the back of the rear seat. Mine lays flat on the floor behind the seat. I took a square of 1/8th plate with a 2"x3" strip of the same 1/8th plate. Drilled a 1/2" hole through the strip and welded that to the plate straight up. Welded the plate flat to the floor. Took a longer strip of the 2" plate, long enough to span the wheel mount surface in the center of the wheel, and drilled a 3/8th hole in the center of that. Went to the hardware store and got a long enough 3/8 "J" bolt, a washer, and a wing nut. Lay the tire centered over the plate welded to the floor, lay the strip over the wheel center and use the "J" bolt to hook to the strip welded to the plate and through the strip over the wheel center and tighten down the wing nut. Now the spare is secured to the floor.
I'll have to take pics of this set up, it's way simpler than all that stuff I just typed out...