Basically what it comes down to is the shape of the wing. The shape of the wing depends on the performance requirements of the aircraft. This is where you start getting into high or low aspect ratio, taper, twist, sweep and myriad other things.

Just like Ben said, the airfoil that you need to use drops out of the overall design. And again, airfoils currently in use on other similar craft are a good starting point for creating a new design. You need to look at a similar craft, find out what drove all the design decisions there, and come up with your own informed conclusions.

Ken - www.litkoaero.com
R/C Aircraft Laser Cutting and Design

P.S. Ben... you got my head cranking from that previous thread we had together. I need to re-evaluate my own design decisions w.r.t stability!