Good suggestions, Harry. I sent you the board via USPS yesterday. I also included a piece of the material that I mentioned previously. If and when you get around to trying the "double-board" I would try with and without the sheet between the boards. Resonance and its effects is a crazy thing and the two boards, as tightly together as they may be held together, will still resonate as thinner boards in, at least, parts of their total surface area; as flat as these boards may be cut, they won't make contact with each other over their entire surface area. The sheet between them may help them act "as one" and will introduce some dampening which may or may not be beneficial in the context of your system and your tastes. At least, that is how my twisted brain considers this kind of thing. Please report any impressions.