I just want to add a couple things here to clear up some possible misconceptions. First off for the introductory classes in both AMA pattern and IMAC any airplane is allowed. For IMAC it is referred to as the basic class and for pattern it would be the sportsman class. The OP has said he likes the IMAC sequences better. An SPA legal airplane will fly the basic sequence well but that's all, It will struggle with the IMAC sportsman sequence due to the fact they don't snap roll well and lack the fuselage side arena to maintain knife edge attitude at slow speeds. The other misconception is that the larger airplane would always win. Not true, I have seen many times where 35% and 40% airplanes were poorly set up and flown and a smaller airplane was flown by someone who had it set up well and was well practiced. Just weekend before last we had a young man flying a Parkzone T28 in basic class. The OP is correvt in that going out and flying a sequence is a very fast way to pick up skills in a short time. Progress will be seen from day one. My suggestion is for the OP to pick up any of the 72" span aerobatic airplanes such as an Edge, Extra, YAk ect. If he is interested in building a kit, then look at RCU, RCG classifieds and see if he can find a Goldberg Sukhoi, Ultimate, Lanier 1/4 scale Laser, Midwest Giles 202 or equivalent. Power any of these with a 2 stroke 1.20 engine with a pitts muffler and he is good to go.