I have an in progress 65 vinyl top car so am interested in this discussion. Like all the GM cars of this era, the glass and trim design was a huge failure. The moisture not only destroys the window opening, but also ruins the trunk floor.
A vinyl top only increases the mayhem. My rear window surround is so completely gone due to the rust that I may take another approach to the rear window. The front I can save.
Anyway, here is another discussion of the window install. I did not think that 3/8 tape was used but would have to check the manual. Good luck.
https://www.chevelles.com/forums/12-...ane-aaarg.html