Fitted bucket seat, but not sure...

[MilesnMiles]

I picked these up from a member recently and after a good clean up they were ready for a trial fit. Initially, they would not fit and sat too high in the car. Eventually it dawned on me that if I reversed the mounting rails everything would line up and so it did. Can't see why i needed to do this, though.
Take a look at the pics, the seats still sit quite high and my head is only about 3" clear of the roof and i've yet to fit the new headliner.
Anyway, any comments welcome. The car was originally a bench seat car which is the same height from floor pan to bum as the new seats, so to speak.