The seat has no suspension, just seat. You need to have a suspension system and your current seat probably anchors to a seat mounting plate which is attached to the chassis with a pivotal roll pin at the front whereby the rear of the seat is on springs attached to the mower.
If you do a www search for "Concentric 44000BK seat" (the manufacturer of the seat) and you select the right answer, you will come upon a mechanical drawing showing the seat adaption dimensions. Note the fact that the rails supplied with the seat are attached to the seat with an adapter bar front and rear, each attached to the seat with 4 bolts which screw into the bottom of the seat.
Simply remove all that and if the seat doesn't have other holes in the bottom to match the mounting plate on your mower, then get a piece of steel and match the holes I mentioned to the slots on your tractor. Piece of cake!
Obvious rear viewing wouldn't be as easy as a low back seat but you don't have to have the head rest at all...pull it out, or push it down if it's in your way. Same with the arm rests, if they get in your way, flip them up out of the way!