Tony,

My boards are much longer than others so I raise them this much for upwind when it's windy. I don't change them sailing downwind any more as the boat feels well balanced with the same place up and down wind; it way be due to the fact that I usually wire downwind, but it was very shifty at Mumbles and the waves were also coming from unpredictable angles. I spoke to JohnP after the first race ande he confirmed he was not wiring down wind for the same reason.