hey atom I installed my headliner on my 69 and didn't remove any glass. its not necessary for simply making it look good. In the front there is a metal peice that goes all the way acrossed the car, just glue it behind that and the metal peice will cover it up. and as for the back, I glued it up on the ridge where the back window is, and then using my hands and a regular screwdriver i pulled back the lip on the weather stripping, and just tucked the end of the headliner under it. Looks very clean and came out great.

I only messed up in 1 spot because I did it out of order, but didn't know of course because its the first time i've done this. I could have fixed it, but i was lazy lol and I'll be redoing it when it gets painted and the windows ARE out.

Also it doesn't look great in the back because my interior sail panel things with the lights on it are deteriorated at the back glass, so its not connected well there. But what I did do looks fantastic and is wayyyy better then the yellow insulation that used to be up there.

 

the rods gave me hell i bought the car with out a headliner and had to buy the rods. if i have to do it again im tossing the rods and doing like newer cars a sheet of cardboard its glued to.

 

I have restored cars from the ground up. And the two things I don't do is exhaust pipe and headliner install. You can't touch the price and quality of a custom exhaust install done at a shop, and the headliner is one fussy, frustrating task. I generally have a pro install the headliner with the rear window out. I have never had an installer want the front window out. In my opinion its well worth the $200-300 expense to get it done correctly.
I have a friend who is in to the rat rod scene. Has a 48 Ford that is all customed out. He does all the work himself. Recently he installed a headliner.It was one of those times where when asked how it looked I had to lie and say "great". It looked like ****. IMO the pro installers no their craft and the results are top notch.