It's not a one person job, unless you get a strap to add pressure properly, even so two people are better and one on the inside on your back making the seal align. It just does not go in easy. There are other issues too. I had my glass out, and a glass specialist said he could get it in. Nope! He ruined my seal and I got another. Then three of us, my painter and his assistant and me managed to get it in.
One of the more difficult tasks on these cars is installing the targa glass. Many write ups on it.
I tried a strap but it just bent the hooks I made up. So it was out. You need to get the trim into the seal before the install, I go new black trim as was the original. Your painter might be able to pull up the old seal and paint around it. This was not to my liking ...
Good luck
Contact these guys, the four of them get it in pretty fast
:
https://www.youtube.com/watch?v=ZZKxcuLekjM