RE: WOW! Another Sig Somethin Extra Build
Heck, you don't need me at all. Tuwood has the same solution that I did on mine. Cut a very small channel in the bottom of the Sullivan tailwheel so that the clevis of the flying wires can go underneath of the tailwheel. Then when you bolt down the tailwheel put one bolt through the two clevises to secure them.
As far as the tail of the plane. I put in two layers of lite ply in the tail (see diagram). I didn't use the blind nuts that came with the tail wheel because if they ever came loose in the tail of the plane there is no way to get back in there to fix them. What I did instead was to drill a small pilot hole in the lite ply and then used a wood screw to cut threads in the wood. Then use thin CA to harden the threads in the wood.
Hope this helps
Ken