I cut the hole for the door to the correct size, allowing for the recessed backing plate. I riveted everything in, even the difficult spring-loaded hinge. I was so proud that it looked so good! Well, when I went to close the door I noticed that the whole door stood proud of the cowling by about a thickness of a piece of sheet metal. Then it dawned on me. The C336 cowling was two layers of aluminum! So I drilled everything apart so I could add a spacer of .032 AL. Lesson learned.
