I did an experiment concerning the sail shape of a sailboat’s sail going upwind. My guess was that if all the wings (they represented sails) were tested at the same angle of attack (more or less as if it was sailing upwind), then the wing with the smallest camber would be the most effective.
I changed the camber (depth) of the sail, and the results of the tests were the effectiveness of each of the sails. I tested 3 angles of attack, on the first two (11°, and 22°) my hypothesis proved true, but on the third (31°) the second to smallest depth prevailed.