Once the hidden spacers were epoxied in, the next part of the hatch structure is the lip. This is where the weatherstripping seals the hole
Using wider plywood strips, I cut and fit the strips to make a single-piece lip.
Using fiberglass cloth for the joints actually worked out pretty well. Even cured, the joints flexed and bent allowing it to fold over and then fit the lip down into the hole.
More clamping
The lip secured and ready for finishing.
The hatch with rubber weatherstripping to keep the hold reasonably water tight
The finished hatch back in place
The hatch with the hold down tabs installed