ptulmer, I'd be willing to bet that among the AMA rulebook pylon classes that 1/2 A pylon (423) is among the least active probably just ahead of F3D pylon (427) in the US. Sport Quickie (424) is rapidly on the rise in activity. I would suggest you ask this question in the pylon forum here at RCU under general race discussion. You may also want to explore the site below to get a handle on things and happenings.
John
Team Geritol
http://www.rcpro.org/html/