If you are talking helicopters, most new gyros will not have any mixing at all. And if you are flying something like the 3GX, then you will go in teh swashplate menu and set it to 3 servo, 120º. If you are using a gyro like the BX or Ikon, then you will set the swashplate to 1 servo 90º. That is all the mixing you really need to do. I have very rarely ever used mixing, and when I did, it was with my 3D planes (edge 540, extra 260 and so on) to stop the coupling when pulling a knife edge. On a helicopter, you should never have to touch mixing, or revo mix.