Mark,
We have some 1/2A scale racers out here in SoCal--but we haven't done much racing with them yet. In a previous issue of the National Control Line Racing Association (NCLRA) newsletter, the Torque Roll, edited by Tim Stone, I submitted a picture of Dave Dawson's racers, including a Falck Rivets (11 championship wins), Long Midget Mustang, Granville GeeBee Model Z “City of Springfield”, and the Wittman Bonzo. We had the GeeBee out at our last race, but had no one to race against....
In NorCal (bay area), they have been doing a lot of 1/2A, including scale and some "proto racing." The contact person for these is Randy Bush of the AeroNuts.
You can see a few photos of Mouse I's from the SoCal area posted at
http://www.nclra.org/As far as construction, if you want to race it, make sure it weighs at least 7 ounces to let you whip on landing. Use the weight to build in durability. The larger scale planes might want to be heavier. Dave's were mostly balsa structure and I don't think they were glassed. His used TeeDees for the "Funny Mouse" rules, but could have been set up for reed-type engines.
Have fun racing!
Dave "McSlow" Hull
SoCal Air Racers