Further to this, I went out and cut a section out of a weatherstrip piece I removed (replacing windshield now) to show how it sits when installed. The pinchweld is in the slot as far as it can go. In this case, you can see there is a gap of about 1/16" at the rabbet ledge and the lower ledge as well. Using GM's method, the rear edge of the seal piece will be filled as well as the lower part. Using the YouTube video method, none or very little of this area will be filled.
You posted the pic while I was typing. To expand on my post, the caulk bead goes on in the 90 degree groove that contacts the roof and flat section of the body. which does the same as placing it on the body first, but with less chance of a mess. Now I'm probably as clear as mud! John
