To be honest, I haven't done much tweaking with planes in realflight. I fly the sbach and I basically increased the throws and expo. It doesn't fly very well, but I find that challenging which I think keeps me on my toes more when I am flying it. When I began learning 3d I bought a bigger epp plane to practice with. I was very bad at building so there was tons of epoxy on it. It flew really really bad but it's all I had so I had to learn to hover, harrier, rolling harriers, ect....with a horrible plane. In the long run, I think it made me a much better pilot. It really kept me on my toes because if I would pull up too much, it would snap out. I always had to be paying attention. Flying 3dhs planes now is a piece of cake because I no longer have to worry about bad habits. This same idea applies to my crappy planes on the simulator. Basically, don't fly planes that are too easy on the simulator, because when you transfer what you learned to the real thing, it will be much harder and the pucker factor will go up.