Ben,
I am not using Marty's wing. Both my wing and Marty's turbine wing uses the same airfoil as the original and both have some added wingspan, but I took all of the sweep out of the trailing edge of mine while Marty left about 5-10 degrees of sweep in the trailing edge of his.
The CG of my wing will be further forward than yours.

On my first ducted fan Interceptor (same wing I am flying now) I did quite a bit of experimenting with the CG location to try and solve the deep stall problem it was having at high angles of attack. I seem to remember moving it fore and aft a total of about 4 inches (2" forward, 2" aft of 25% MAC). At the more forward positions the elevator became less effective, and at the more aft positions it became more sensitive, but other than that it didn't really seem to effect the way it flew.

My suggestion would be for you to figure out the MAC of your wing and set your CG at about 27%. I think it will be safe to fly it there, and then you can change it to suit your own taste later if you like.

Good luck,