Thank you for that information. I will introduce a very slight prebend whilst at anchor, then go and test it as you suggest.
Whilst on the subject of the mast and rigging. I have not been using the running backstays much as I have been reaching up and down the islands in the West Indies.
However I will be sailing back to Europe this May and will most likely have a good thrash to windward, at least for the first few days, and will use the runners accordingly. However I feel that they are hardly necessary in all but rough conditions to windward, as the spreaders are swept aft. Thus the lower spreader and the baby stay triangulate and the upper spreader and the staysail stay also triangulate. Up to now I have seen very little or no pumping of the mast, even when sailing upwind in 15-20 knots true wind.
Would you agree with that approach?