Any tips or tricks to installing rear window and seal on a 71 Duster?

x2.

Best tip.... Hire a glass guy.

Doing your own glass work just isn't cost effective or a matter of pride. It's being smart.

You get a leak..... It's covered under your warranty.

Yup. My rear is leaking on both sides. He's taking care of it for me next week. These new seals these days are iffy. Just not the same quality.