I wanted to add a headrest to the rear seats for both comfort and looks. The rear seat uprights are very severely rectangular and blocky. Adding to the top of the seatback is very problematic from a structural standpoint with little to attach to.
I welded (with my very limited aluminum welding skills) an aluminum angle addition and riveted to the top angle brace. I had to cut the top of the seatback skin off and added a skin extension to tie everything together. This will be set over to the upholsterer to add the foam and cover.