The way we positioned outboard brackets:
*We covered bottom of brackets with packaging tape and scuff sanded
*We put packaging tape on headrest covering and scuff sanded
*Drilled cover and screwed bracket to cover and put some JB KWIK on mating surface
*Installed cover and screwed in place, once epoxy set, removed screws and they are temporarily bonded as you see
*Just drilled in position and hence a perfect fit.
Y8-12-12