I learned on 3 channel planes and am currently flying a 4 channel PZ T-28 Trojan with great success. The thing is, 3 channel or 4 channel, you will still use the right stick to bank/turn the plane. I personally don't use much rudder on my 4 channel either, just to taxi and maybe land sometimes. The key for me was to use the dual rates on my Spektrum DX6i. I basically just turned down the throws to aileron and rudder to 60% and elevator to 75% and went from there. It made my Trojan much easier to control. As I get more comfortable with it, I may just turn the D/R off and run the control surfaces at 100%. Locking out the ailerons on a 4 channel plane is really not a good idea. After all, if you want to fly a 3 channel plane, buy a 3 channel plane. Very strange advice.