Changing the CG is just a simple math calculation. No big deal. You simply combine the cord of both wings and go back 25%--30% on the forward wing to balance the plane. There are some basic ratios in aircraft design that should be followed. Thats why I think it would be a good idea to stretch the tail out a bit.

The more I think about it, the more I want to do it.

I'd have to put some hardwood blocks in the wings for cabane attachment. There would also need to be a hard mount in the nose somewhere for the center wing support. None of that is extremely difficult.