On my CH yoke, I use the rocker switch on the top right yoke handle for left and right aileron, and the button on that handle to center the aileron. I use the rocker switch on the left top yoke handle for the elevator trim and the front button to center trim. i find this more precise than assighning an axis for trim. Many times an axis will be a little noisy, and a bit twitchy for trimming. In X-Plane aileron trim is essential, the only planes that I have that do not need aileron trim, or very little is the F33A Bonanza from Carenado, and the Piper Archer III from MortonM, (an excellent freeware plane), even these still need a bit of aileron trim from time to time. Be aware each time you make a power adjustment you will have to retrim both aileron and elevator trim.