Any tips or tricks to installing window felt?

[C&C Chevy]

Thanks, Jeremy!

On the first door I removed the 3 screw and the bolt holding the vent window in place, so I could wiggle it around like you mentioned. Sprayed the rubber down with some soapy water and it went in pretty easy.

The second door was a PITA. I left the vent window alone to see if it would go in just as easy. And it did not. Had to keep rolling window up and down just to get a 1/4" at time down the track.. oh well. Job done!