I use a 6XAS. You will need to use a programmable mix. Ch2 would be the master, and Ch 5 slave. If you are also using two aileron servos on Ch1 and Ch6, you will have used all six channels. The programmable mixes are very easy to use. Just read the manual and play with some loose servos. Don't forget to set the mix % for both directions of stick deflection and use the right sign (+ or -) to get the correct direction of travel.