I don't know John, I have had real good luck with low wing planes and would never consider high wing over low wing as a prerequisite. My feeling is first you look for the carrier plane that had the least frontal area and then you make some drawing (maybe lots of drawings) to see if you can build the plane close enough to the "PROFILE" carrier rules so that anyone who looks at it can say "oh I know what that is, its a whatever. If it is a low wing plane you have another advantage, you can line up the engine, fuel tank, and the thickest part of the wing to reduce the frontal area that much more. As long as the trailing edge of the wing appears to be at or near the bottom of the fuselage the plane will look OK.
The Bf 109T, the F2G-1, and the Seafire MK 45 that I fly are all built in that manner and have always past the muster in scoring. This is the beauty of the "AMA Profile Rules" they give you quite a bit of leeway when designing and building the profile carrier plane. I've always felt that its to bad the AMA CL 1 and 2 plane cant be built the same way. Then you could put something together that could compete with the MO-1.