Here's an article that may help:  http://www.limbobus.org/poptop.htm

That's the way I did my canvas change. Help from John Carpenter, my Salt Lake neighbor, kind enough to help me out with several changes/upgrades/maintenance procedures.

Taking the top off made it so easy to put the canvas on and be sure it was properly centered and stretched at the front corners, and that led to applying the canvas to the roof top, or "bottom" of the pop top a breeze. I used a Black/Decker small electric cordless screwdriver which has an end or handle that folds/bends so you can get it into the tight space at the rear when you're installing the bottom screws ('87 Syncro Westy).

Bob
Salt Lake