The rear was too wide, I considered narrowing the tailgate but it was okay. The "C" posts were okay. I found the upper Chevelle fenders were too bulbous. So they had to be cut out and will simply be repositioned.

I straightened the fender pieces slightly and fit them. That's much better.

Here's the best method of testing dimensions. You can see that the roof needs to be lifted a smidgen but window is fine. I love doing this Photoshop stuff. Notice the drip rail is alligned in one long straight line. Luckily, I haven't glued down the roof halves yet.

I don't have a really have a good reference photo of the roof. Especially for that mid-roof angle. Ideally a photo would be taken from a bridge looking straight down at the roof. This is the best solution that I can come up with.

Added the rear window sills. Also note that you can see the shims I added under the "B" post and the"C" post to to correct the driprail angle as discussed above..

Studying the reference photo, I see that the drip rails aren't in a straight line. Now I still have a chance to get it right.