If you check the specifically designed pylon airfoils in the post in destructiveTesters post you will find each and every one is slightly cambered. They also have a somewhat reflexed trailing edge to address the moment problem. I was not trying to define a specific airfoil design but only voice a general principal. (with which serious designers seem to concur). It is seldom the case that a symmetrical airfoil is the absolute optimum choice except for flying upside down.

There are so many factors affecting the overall performance during a race, it is unlikely that a small difference in airfoil will usually be the deciding factor. As in most competition, the rules are written so that a major factor will be pilot skill and technique. In other words, one pilot may win with a merely satisfactory aircraft, and another may not, even though his airplane is better. This isn’t to say the designer shouldn’t strive for an optimum machine, it’s only that that alone seldom determines the outcome.