Kevin,
If you check out the other fun fly type planes (profiles) as well as the 3D types (laser 3d etc) you will notice that they also have relatively few ribs. Don't worry, the covering adds a ton of strength and the camber of the wing also helps.

JL636,
My CG is at 6-1/8" and the airplane flies great. Nothing scary about it; the huge wing and large controls will take care of you. Definitely program more rudder on low rates. I took the book's advise, but I should have trusted my instinct.

By the way, this plane will pinwheel really well!