You won't be able to get this properly adjusted with a Y harness.
You can't adjust control horn position and have the throws equal at all points. What you need to do is put each servo on a separate channel, adjust the center point so that both arms are at whatever deflection you want, and then adjust the end points. As long as your mechanical connections are even, you will have the same throw on either elevator.
ORIGINAL: jbloom
I do have a "Y" harness connecting the servos together. Certainly wouldn't hurt to split them up. Just pick up a couple extensions.
However, leaving things as they are, I guess I'll adjust the control horn position until I get them to throw equally. If that proves to be a pain, then it's off to the hobby shop.
What two channels do you plug them into? I have a Sig Somethin' Extra with ailerons in 1 and 6. I suppose I could use channel 6 with elevator. Thanks for the input.