I got to test that on a Stryker that needed new ailerons. The stock one are flat with a rounded trailing edge, and I made balsa ones with a pretty sharp trailing edge. I couldn't tell any difference in speed, but I did notice that the controls were softer at the middle, which would indicate that they are less effective/ sensitive at low throws. Obviously, that's just one plane but I actually was able to reduce the exponential in my radio a bit and keep the same feel in the center.