You can cut your cardstock to the approximate size and transfer it to a piece of light aluminum sheet. You will need to work the aluminum to get it to lay in the correct position. Here is one thing that you have not considered. No airplane, especially a warplane from this era is too slick. They were not built to last very long, and were not pieces of art. They were very rough in places. If not that rough when built, by the time they got to a line squadron and the mechanics had a part off and back on several times, the part would be scarred, gouged, hammered and patched.

Bill, Waco Brother #1