I decided to deviate from the plans here. Instead of stopping the aluminum at the end of the roof, I decided to bend the aluminum 90 degrees and have it stop at the bottom of the hinge spar assembly.

In the event of water seeping under the hatch hinge, the water would drain into the galley rather then go into the roof subsystem where water damage & rot would go unnoticed. The aluminum also makes a better mating surface for the hatch gasket.
Preparing the Aluminum Skin