Excellent work on the louvers. The blades you've made look awesome. I like the look of molded plastic louvers(difficult to find), but metal is more durable(and repairable), and can be made to look just as good as the plastic ones, perhaps even better than plastic, with polishing(thanks for the idea, hadn't considered it). If I were to attempt to make a set of louvers, I'd use the same inexpensive flashing material to practice/pattern it out. I would like to make a set of metal louvers with a bead rolled along the trailing edge, for added rigitdity and a bit more dimension to the blades, and to give me a reason to buy a bead-rolling tool.
I'll have to post a pic of a set of metal louvers I have that have some tubing as their center support, all riveted together, just to give you another idea to work from.
A few posts back, someone mentions louvers for the current Mustang being attached with douple-sided tape. Its probably a real bear trying to clean the road grime out from underneath the louvers. Louvers must be easily removable or hinged to allow for cleaning. I'd plan on mine being hinged at the top and having some thumbscrews to hold down the lower corners(something nice, not just wingnuts).