68 barracuda fastback rear glass installation

Thanks Murray I understand that once the glass is in the easy access is gone. I am thinking like Professor Fate stated I can place all the interior trim loose in place, then install the glass. then tighten up and adjust the trim? Problem is I am older and fatter than I was when I started this car 20 years ago. That X bar is hard to get around.
I started the car as a pro street deal and when I sold it my buddy went more pure drag, so I am tugging between the 2, barely street legal or a sportsman drag car.