Mark - your layup schedule is similar to what I used when I recored Rhapsody. I used 2 layers 17oz bi-axial fabric with the build in 8 ounce mat on one side for both outer and inner skin, strengthening the outer skin because it was paper thin in spots. The built in 8 ounce mat makes it easier to get a smoother surface for fairing.

I also used a product called Core-Bond instead of thickened epoxy to bond the balsa to the skin. It comes the consistency of peanut butter and you just mix in the hardener and trowel it on. It's much easier to work with and is easily sanded.