E-Flite SUPER AIRLINER TRASMITTER SET UP

Hello i just finished my SUPER AIRLINER......what a good looking plane .
I put 2x 400 e-flight motors 2x e-flight 20 amps esc and 2 tp 11,1v 2100 lipo batteries and 147 f FUTABA RECEIVER.
At the moment on the aileron servos i put an y but i can use flap....
Can you tell me how to doit and if i have to put each aileron servo in a different channel for flap without the Y on them ?
I have the FUTABA 9 CA trasmitter wich is the menu to set flaps fonction and how i have to set up.
Can you tell me also how to set up dual rates or other things to make him work properly.
Also what is the best position for the batteries to get the best balance ......
Thank you all for your help