Joe, my seat does not touch the floor pan in any way at all. My seat is an al. seat so I welded a 1/2 X 1 inch steel tube between the side rail and the tunnel. The seat is bolted to that.
With a fiberglass or similar seat with side mounts, the side mount can have a tube welded (or attached in another way) that runs front to back and can then be attached to a cross bar that is attached to the side and tunnel to keep the seat and the mounting system from being in contact with the floor pan.
My seat is about 1/2 inch above the floor plan so the floor has room to buckle without touching the seat bottom at it's closest point.
Any flat metal attached to the floor pan will, perhaps, help some but will not be very strong because it is flat.
The floor pan buckled in every significant crash I have looked at. Mounting the seat on the floor pan is , simply, not the best way to mount it. Any movement of the floor pan allows the top of the seat to move several inches and can allow an impact with the roll cage.
My 2 cents for what it is worth. Of course, remember, you always get what you pay for.
Jim