Did a quick reassemble of the old parts back on the new configuration to see what needs to be addressed. Wow...I really slopped this aero cap together...just not as bad the first time.
Picked up some aluminum angle today so I can lose some weight from the hatch. Hopefully it will pan out.
I figure I should be able to use some spray adhesive to attach the template to the flashing and then trim and bend accordingly. It should prove to be an interesting start into metal work.