I am making the hatch for the tongue box the same way as the galley hatch (Steve Frederick's method). So this is good practice when it comes time for the galley hatch.
I cut my 1/8" spacer and 1/2" off set for the seal
This is the 1/8" thickness and 1/2" thickness offset pieces
The two pieces laid on top of each other
Cutting the piece out that will eventually end up being the template for the 3/4" piece the seal will attach to (Note the 1/2" offset between the two pieces)
A few examples of how the seal will lay in the hatch
Example of how the seal attaches to the 3/4" piece and opens with the lid
Gluing the 1/8" and 1/2" piece to the tongue box side wall