I rigged up my seats for direct mounting to the floor pan. I'm not using the optional seat tracks in order to lower the seat bottom so I can look through the windshield and not over it. The floor pan is pre-drilled and because the holes are reinforced I wanted to use them for mounting and I didn't want to have to drill a bunch of additional holes in the floors. Another issue is that the floor is drilled for mounting on 12 inch centers but the seat mounting bolts are on 12-1/2 centers.
I bought some 1-1/4 x 3/16 inch metal strap and cut a piece for each side of the seats. Then I drilled holes for bolting to the seat frame and holes to bolt down through the floor - both on the required spacing. I scooted the driver seat back about 1-1/4 inch measured from the front bolt holes and seat mounts. The passenger side seat went back about 3 inches. It was really forward. I countersunk the holes and used flat top, countersunk 1/4 inch bolts for mounting. I used my marginal welding skills and wire welder to tack the bolts going through the floor so I don't have to worry about holding them on top while tightening them. I had some 3/16 inch thick washers left over from something and used them between the seat frame and the strap at the front to tilt the seat back slightly.
All in all it worked out pretty well. I can drill some additional holes if needed and scoot the driver seat back about another 3/4 inch. But, as it is right now I'm going to have to adjust the clutch pedal back some so I can fully depress it without fully extending my leg and stretching. The seat feels solidly mounted. This second photo from the botom is the passenger seat which I had to set back quite aways.
