Rick, a friend and I have built one of these. We used one layer of 3/4 oz. (on the outside) a layer of 2 oz. and a layer of 6 oz. It feels a little flexible when put together, but the nose gear former stiffens it up quite bit.
What engine and fan will you use?
Ours really performs on a K&B 7.5 and Turbax fan.
The OS 46 VX would even be better.

Good luck,
Jim