I need some help with the reccomended setup on my radio.

I have a plane with 2 Aileron servos (1 each half)
1 throttle servo
2 Elevator servos (1 each half)
1 rudder
2 batteries for receiver
1 R138dp PCM receiver

Could you tell me the best way to setup this airplane

I think what i need to do is activate Flaperon mode and Select a mix Program mix 1 and turn mix on and master would be Elevator and the slave would be aux 1 or 2. (Does it matter witch slave i use aux 1 0r 2 ?) I think link would be off and trim on, the switch would be set to null. Set the percentages on the next page to 100%. I still want to have all functionality of trims and sub trims to match the surfaces up.