I also spent some time today working out how to build as hinge for the map box door that will give a nice flush finish, and my answer came in the form of the concealed hinge I'd bought at Oshkosh for the oil dipstick inspection door.
Using this concealed hinge I was able to come up with a design that works. My pictures below show how.
I'll finish this off tomorrow.
Now I just need to buy another hinge for the oil hatch.