That was my biggest fear when learning to fly (well, I'm still learning) coordinating rudder and ailerons together. My radio can do it, but I've never even thought of trying it, and I've never used that mix, I simply tried to learn it the manual way.

The first dozen times using rudder on my trainer with the ailerons usually resulted in a major loss of altitude, but since then I can comfortably turn using the rudder with the ailerons.

I think it's definately best to learn to do it yourself, that way you don't rely on your radio or y-harness to fly your plane.