Hi Al Hope you sort things out OK.
Your story brought back another memory, back in the late sixties I made my building board from 1" block board, which I mentioned previously, I made sure it was dead flat by screwing two 4"x2" PAR timber rails to the long edges, it weighed a ton but stay flat through many builds, including a Dave Platt 65" Spitfire kit which was my first eliptical wing with washout. I also used it to decorate ceilings between two home made trestles.
