I know basically nothing about bodywork and all that,,,but it looks to me, judging how the gap is wider at the top and then closes up at the bottom edge of the door....that the quarter section of the car is out of alignment. It seems the door hinges and front of t-tops are ok,,but the car ''pulled away'' at the back side of the t-top and door,,and is pivoting/bending at the lower rocker area (?)
I'd definatley try jacking the furthest part of the rear of the car up and see if the gaps close. How is the frame?? Bent? Rusted away?
how about body bushing??? body bushings fixed a whole lot of alignement issues I had up at the front end.
Also,,try sighting down the middle section of the roof front to back and see if that piece looks 'effed up.
I remember a similar issue with old convertible corvettes. The conv roof would be too big. A measurement from the top of windshield to edge of the body behind seats would prove that the windshield pillars (A pillars?) rusted out down by the firewall area and the windshield was 'falling' inward.
thats just how I'm picturing this ,,but opposite direction.