I too just fought my way through a rear window seal replacement. I used the Chevy Duty seal. Brace yourself for a bear of a job. I had the window installation tool that they sell, and I don't think it can be done without it. The only trick I stumbled into was to use Armorall instead of dish soap. It is plenty slick and is supposed to be a rubber preservative as well.

Good luck. You'll need it.

'47 1 ton

Don't read the directions, that'd be too easy.