RE: DX7 Mixing Ailerons and Elevators Together
In thinking some more on it, might just be a little easier just increasing the throws on the ailerons on the bird, and the ATV on the tx.
More of each would give you quicker response in a roll, and would save you a lot of time trying to set up the quad control surfaces to work in harmony.
Also moving the CG back a tad will make it respond faster.