robert, pond size isn't as much of an issue as you might believe. these boats turn on a dime & give back 25 cents change !! they don't slow down in the turns, they unload some & accelerate through the turn, so maintaining speed also isn't an issue for pond size. while the .12's seem to be more popular in the northern midwest US, the .21's are a more common race class. i love my .21 jae, everything it's advertised as, & then some B) . whichever one you choose, it WILL put a bigazz grin on your face.......