I used the clear plastic back window to make the rear of the roof, as Ghia used the very same contours in sheetmetal as were in the hardtop rear glass. Amazingly, the "glass" from the kit, once cut to shape, will fit more or less flush, only a bit of filling, filing and sanding needed. All filler used to this point, throughout the bodywork is Goldberg SuperJet CA glue, with Bob Smith Models Accelerator. The upper edges of the side window openings were added, using .060" square Evergreen strip styrene, as are the two B-posts. My personal practice when installing B-posts is to file a notch into the bottom edge of the side of the roof, and a corresponding notch into the upper edge of the door area, so that the posts fit flush with the inside edge at both bottom and top, and being set in notches, the glue joint is virtually indestructible. I did file off the upper portion of the windshield trim, in order to smooth down the roof, then added it back with Evergreen styrene strip, blended in with CA glue, file and sandpaper.
Here's a couple of views of the project, pretty easy one to do, BTW:


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