you may want to reconcider alum. flashing, go ahead and make your template as close as you can then transfer the shape to flashing. after you cut the flashing you can anneal the alum to make it softer with a propane torch, put soap on one side and heat the other side till the soap melts and turns black, then that makes the alum softer, then work the area to shape. may take several heat/bending attempts to get what you want.
after you get your panel on then work it over with steel wool start with 00 then progress to 0000. if you want a bright polish get some alum polish and go for it

hope this helps
todd