I fabricated a polycarbonate backing board for the circuit board, separated by standard AN960 washers. I then mounted nutplates to support it inside the tunnel. Next I'll make spacers to hold both boards away from the metal, incuding the seatbelt bracket. When I'm ready, I'll fill the edge gap between the circuit board and the polycarbonate with RTV to stop anything metallic coming in touch with the circuits.
