if you're worried about securing the plate in the cab wall, drill some xtra holes, get your nut plate up there, plug weld it in place ... for the lower attachments, fixing them to the seat in any way is foolish, they'll find the seat on the pavement with you still belted to it - drill the floor along the ridge behind the seat [as factory directed], which is a multiple layers thick structural piece, and if you want stronger put a piece of 1/4" x 2 strap steel across each pair of attachments below the floor
Bill
