Thanks for the nice comments, I always hope people enjoy seeing the stuff I put up in my CAF portfolio
As for watercolours, I suspect it depends on what type and how much are used. I've got some new Stan Sakai coloured pieces that are on Bristol no much thicker than that used by Sophie, and they are fine, but I do have a
piece by him that has buckled a bit too. Possibly changed watercolours over the years. Most of Stan's modern watercolours for the trade books (covers and tip-in plates) are on 4-ply or 5-ply board, much thicker and can withstand repeated water paint strokes.