[dsraven]

sometimes instead of the flexible board I have stapled one of the sanding strips to a piece of plywood the same size as the board. it doesn't flex at all so the really flat parts come out really flat. some wax and grease remover on a rag with a nice bright light across from you, reflecting across the surface, works pretty well to make things glisten and you can tell right away if there are any ripples etc. it would look like it would doing the same thing with fresh paint, except this way you have time to fix any ripples before paint time. less cussing that way, lol.
yours looks good. must be nice to have pretty good panels to start with.