the old PP is painted yellow. Is that a McCleod, or a Weber color? Why not ship it back to manufacturer and get it rebuilt? It worked for 45 years, right? Just freshen it up.
McLeod was red for as long as I can remember (1979) and I don't remember who was yellow. Back in the day...the DC clutch was green. It's possible that PP was rebuilt by someone who planted it their color.
I agree with RC69. Have the PP you already have rebuilt and use a new disc and be done.
Just remember as the disc wears the finger height moves closer to the throw out bearing. So...the thinner the disc, the higher the finger height.