Duster Rear Window Louvers

For anyone using "f" body louvers the only thing I have come up with is to cut out the window shape on the bottom side of the louver. Then I'm going to try to cut the leading top flat edge off shape and attach it to the cut out I already have cut. If I can dremel the edges to get it to fit, I might have a descent template to use for fiberglass, or maybe vacuum forming.. I'm open to other suggestions. Anyone?..
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