RE: Hooking up two elevator servos with Spektrum 7600
Both will work but if you do that you ignore one of the most powerful features of your new radio - Channel mating
Press and hold ENT and turn on the radio
Scroll to DeviceSEL
Set the channel you want to use for a mate to INH (bottom line) lets say AUX2
Go to the WingTYPE menu
Under ELEV press the wheel and it will give you the free channels, select AUX2
Now, when you return to the menu instead of ELE and AUX2 you will have LELE and RELE (Left and Right Elevator servos)
Plug them up that way
Now you can sub trim and set the direction on each servo. In additon, the trim will effect both servos, unlike using a pre-mix where it only is active on the primary channel