John, in your other thread I pointed you to the FAQ about fitting windows. In there (as Pablo mentioned above) it was suggested to fit the rubber to the body opening and cut it a bit long. That's important so the rubber won't pull apart as it shrinks. On the cut ends I have used flexible urethane adhesives. However, if you remember to cut the seal long you can get by using black RTV, or even cyanoacrylate glue. However, if you get the ends cut really square you may indeed not need sealant/glue like Pablo said.
Hi Doug
Well, it is now fitted, and i have got away with not using any adhesive. I cut the seal about 10mm too long, and it squeezed in OK. Bye the way, i thought the rear screen went in much easier than the front. contrary to what some people were saying.
As for lubricant, i used car biody shampoo/soap, and that seems to have done the trick in order to get everything in. I still have to install the locking strips though....