So that picture shows a real bad warp on the canopy hatch. I am guessing both the front and back edges are lying on the table. You might try to heat the entire hatch with a heat gun and get it to relieve itself back to its original shape. That is probably from the years of sitting and in some warm environment with some weight on it.
So the original used pinned nylon hinges from its conception. And a .055 wire for the pin the length of the flap. It should be shown on the plans and in the manual.