R,
Sounds like a very reasonable setup. simply setup flaperons, and, if you want htem to work in conjunction with your flaps, do a mix from your regular flaps - ch 7 - to your flaperons channel 6. Then be sure to use a flap to elevator mix as you're definitely going to see some ballooning with that much flap area....

You might look at the setup for the ultrastik on our FAQs to get a better idea.