The only thing that I have ever worried about when designing a wing is that the Spar supports the wing at the apex of the airfoil (the fattest part). The spar (The fattest part of the wing) should be at 25%-30% of the total chord of the wing, measured from the leading edge. The ailerons ARE included in the wing chord measurement. I've built and flown over 300 wings using this simple guide, and they have all flown. Fat ones, skinny ones, flat bottomed, symetrical, simisymetrical...you name it.

I also try to keep my wing loading down to less than 20 ounces/square foot for good solid performance. good dead stick glide, and better stall charicteristics. This is the size of your wing as it compares to the weight of your airplane.

Wing loading is the weight of your plane in ounces, divided by the area of your wing in square feet.