then you need to a little higher.
the purpose of the spacers under the seat, is so when you lift the bottom of the seat, the seat back also rises and clears the clasp , mounted on the back wall. the other way to have the metal hooks, on the back of the seat itself, clear the clasp mounted to the back wall, is for the hooks themselves to be trimmed enough, so when the bottom seat lifts up, the hooks can clear the back wall mounting.
either way will work. benefit of the spacer under the seat bolts is it can be undone and none the wiser. trimming the seat back hooks is not reversible.
also, benefit of raising the seat bottom by spacers is now there is more room under the seat, when it is down position, for sunshades and the like. however, if doing the spacers, I would recommend buying replacement seat bolts that are slightly longer than OEM so the seat is secured, to the floor of the cab, as designed.
In case of catastrophe, if given a choice between the seat coming undone, by the rear of the seat moving forward, while the seat base is still anchored to the cabs floor by bolts, or the seat base coming undone from the cab floor itself, I know which one I would prefer. if the seat back should come forward, the seat belts would help to restrain any passenger and the seat back itself. If the entire set becomes detached from the floor, acct too short bolts, all bets are off.
Hence the suggestion for replacing the OEM bolts, with longer versions, if using spacers.