Bosswrench - Appreciate all of the tips.
I don't recall seeing any aluminum spacers when I removed the seats, but after replacing the old rollers with plastic, the seats seem to be moving fine after installing them.
I do plan on improving the driver side cushion - the seat backs and the passenger cushion aren't too bad so I will leave them alone.
I do like the look of the thin original seats from a design/style point of view. I feel that the big modern cushy seats (they do look comfortable!) that I see in some Panteras look out of place - especially given the minimal interior space.