The rear window recess I did took ages and lots of bad language! It looked really great when complete and with paint on it.
The problem came when we fitted the rear window in its new channel, it sat proud by a good few mm at the bottom corners.
Because there was very little pattern left I based the bottom corners on the top ones, the shape was right but it didnt take into account a slight camber on the actual metalwork on the back of the cab!!
It was too late to do anything the the painted metal so we ended up very very carefully using a file to take some rubber off the window channel, in the end we did enough to make it fit and it does look right.
I totally understand frustrations in this sort of situation and think all the more when you see results like you are getting.