Some thing else to try for gluing that rear deck back on is JB Weld. It is made for repairing metal car parts. It is a two part putty & when dry sands very well & feathers nicely. It comes in two types, JB quick & regular that dries in 24 hours. You could tape the pieces together & fill the area with baking soda & thin CA glue. A really nice two part auto filler is Evercote , polyester glazing putty. It is not hot & sands very well & feathers nicely.
The Cuda is coming out nice, so far. Like what you have done with a wreck.
You could carve a master of the windshield you like & vac form it from clear acetate. The idea of the Calloway Vette windshield would look cool. You could use the interior & headrests as well.