How replace rear quarter glass?

[Formerly Steve Wilkinson]

Did a search but nothing came up:

I'm replacing the fixed rear quarter glass on my '83 SC with Plexiglas. I'm using 964 seals even though it's a 911.

Does replacing these seals and the glass within them require the same string-in-the-groove trick that's required for windshield replacement, or can you simply push them into place and work the seal into place with your fingers?

Also, am I making a big mistake using 964 seals? I originally bought them because I assumed they wouldn't require the metal trim strip (which they in fact do require). They look virtually identical to 911 seals, but was there some minuscule change to the body structure that means 964 seals will never fit into a 911?

Oddly enough, I had no trouble replacing these windows five years ago...but I forgot how.

The mind is the second thing to go.