OK, a little late completing the project, but here's a little different method. Maybe not as pretty, but I'm all for simple. easy and effective.
This one's a pre-assembly view with a shim used to facilitate the hinge opening that also visibly balances the box. The hinge is SS:
Pre-assembled showing the thumbscrew/rivet nut and weatherstrip mounted on a riveted AL tab:
Completed/secured assy:
Hatch open: