I used the rope method to replace the rear window seal.
Put the seal on the glass
put 1/8 inch diameter rope in seal where the steel lip of the car body will wind up
place the window and seal in the opening and pull the rope out from top to bottom.

I dont know if this makes much sence. I wish I had taken pictures. Once you have done one it's easy. Always learn on rear or side glass because its really hard to break. It's really easy to crack a windshield so it's best to have some experience when you tackle that job.