I have wind tunnel measured polars for the MH 32 but not for the MH33. Also, Martin Heperle's web site is discontinued so I don't have access to the MH33 polars as generated by X-Foil. The lowest drag measured in Dr. Selig's series of tests at the University of Illinois was for the S6063 with a little reflex inaccuracy in the trailing edge of the test model. The S6063 has a thickness a hair over 7 percent so i don't think you need to go thinner. If Heperle recommends the MH33 for pylon racers, it should be one of the best. It sounds like you are flying an almost circular path over much of the course. I'm guessing that you are probably not exceeding a lift coefficient of about 0.5. This probably means that the induced AOA is only around 2.5 degrees and the total AOA excursion doesn't put the fuselage in a pitch attitude with hgh drag. My conclusion is that the zero-zero setup is close to optimum.