Just one other tidbit...

IF you find that after mixing aileron and elevator you're lacking some channels...say for smoke or what not...you can also use one of Smart Fly's Equalizer II boards for either aileron or elevator. I use them for both on my WH Edge, and they've worked flawlessly through 100+ flights. They're fairly inexpensive (< $50 iirc).

Personally, i also find the setup of them to be simpler and quicker than mixing in the DX7...but again, that's just subjective preference.

Nothing wrong at all with mixing in the radio, simply offering a different way to go about it, with its own benefits.