'88 GT Convertible Weatherstripping

Need some advice here on replacing the weatherstripping on a 1988 GT Convertible...

The inside stripping I think I can handle, but it looks like I might have to remove the window glass to get to the outside rubber. According to Chilton/Haynes this will include drilling out a couple rivets. Now, the only window glass I've ever worked with before was on an old Fiesta long ago and I certainly don't remember have do any drilling.

I'll be calling a few body shops today to get pricing, but does this sound like something I'd be better off letting a body shop get into or is it still a relatively simple operation once the trim panels are removed?

Also, does it really take the removal of the rear seats to get the quarter trim panels off? I was having trouble getting the right pressure on the rear bench to slide it back and free of the retaining brackets, as was the help at a nearby Autoparts store I went to for some advice. He was under the impression that the trim might be able to come off without taking out the bench, but he wasn't positive.

Hope you guys can help!

Rear Well?

Standing in the rear well makes me think you're actually standing on the floor rather than on the seats. Don't you have to put downward pressure on the bench to get it free, or can you simply push the unit towards the rear of the car and be fine?

AH, wait, I think I'm getting it. Don't put pressure on the cushions, as the parts-guy was showing me, but actually on the rigid section of the bench close to where it meets the carpeting?