When using a Y harness, you will have to run the arm positions of the servo opposite to the other. You will also probably have to turn one servo 180 degrees for the proper rotation. An easier way to do the set up is with Futabas' equivalant of JRs' Matchbox. Both servos plug into the Matchbox and only one wire from the Matchbox goes to the receiver. Both servos are set to the same position with this method.

If you are using a high end computer radio, the servos plug into separate channels in the receiver without a Y harness and the servos are "mixed" using the programable mixing available in the radio. The elevator becomes the "master" channel and the other servo becomes the "slave".