Hey hows it going everyone.
Hope this info might help a little, as I recently tried to do the same thing.

After trying to use mixing and plug the servo's into the receiver separately, I ended up using a "Y" lead to connect the two servo's, and a programmer to set the servo's up.

At first I thought that I would try mixing the two servo's,eg: ch2 and ch5(like you mentioned)
This seems like a good idea as you eliminate a weak link(Y lead) in a dual elevator setup.
However when mixing like this with Eclipse I found that it was a little tricky as you cant assign, or de-activate switches.
The mixing part is pretty easy, if you have a manual it explains how to use the programmable mixing on page 17.

I used CH2 as master elevator, and CH5 as slave elevator.(MODE 1).
CH6 and CH7 were already taken, CH6 was my left aileron servo and CH7 was fuel mixture, so CH5 was the only one free.

The thing I didnt like when set up using the mixing was that you cant turn the switch or knob off for CH5,(elevator slave servo),,,, this means that when you moved the CH5 switch it would move the elevator, I thought this would be a little dangerous. It gets pretty messy with the mixing, and you might also find that in some circumstances the elevators are not working properly. Like if you hit the flap switch and dial in some elevator for pitch correction, I found that only one half moved,(it forgot to move slave servo), also I heard some problems that the trim only moves one half.

As already mentiond I ended up just using a "Y" lead. With the "Y" lead you know both servos will move at exactly the same time. Thats what I liked about a "Y" lead.
"Y" lead was much more simple and works fine, only thing if the Y lead breaks I lose all elevator control.

Hope this doesnt confuse you all the more. Also why didnt YOU want to use a "Y" lead?


Good luck
CYA