RE: C/G for Tandum Wing
I don't know where he got those numbers but given the results of the CG calculators that sounds very nose heavy. And even my gut opinion from considering the layout that I see in my mind's eye I'm sure he's way too nose heavy to fly well. But it's his model.
Besides, the whole concept of pivoting the motors seems flawed to me anyway since it results in the wings both trying to lift off the ground with negative angles of attack.