You can see pretty much how Gary did it by looking at the location of the A-pillar attachment point to the body, and where the C-pillar attaches. He explains also how he did the glass. Something so difficult in my mind shown to be done so easily.

Stop the video at 1:28, you'll get a good side view shot of where Gary reattached the roof to the body. Look at the leading edge of the door line in relation to the A-pillar. Also try to catch where the C-pillar attaches compared to the trunk line. If you have the kit, compare the body to what you see in the video. Hoping I'm making sense.