K4 all the way, you want to learn the 109's you might as well learn how to fly the "beast"!! K4 has been given a bad rap when it comes to maneuverability, though It's not the best it is good enough! and the extra speed, acceleration and climb rate make up for what it lacks in maneuverability. The 30mm is the big obstacle in this plane, but once you get use to it, the game is on!
Cajunn