I may get labeled a freak, but I use Thumb on left stick & Pinch the Aileron/Ele.
I dont use a neckstrap, so I have to have a good grab on the transmitter, and cupping it into the left hand leaves only the thumb over there. Meanwhile, I can pinch the right using just a little heel to steady the TX.

Works for me, but I'm mostly a bank & yank flyer. Rudders are for folks with wheels on their planes.