RE: 4.0 m2 sail with 400 mast (luff 376)
Good morning, Tom,
For many years, I have used a 4.0m sail with a Vario Top extender, which allowed me to use the sail with a 400mast, rather than the recommended 370. May I say that the sail was only used about 8% of all of the time I spent on the water and I thought it was cost-effective not to buy the correct mast (as per James, above).
Recently, I decided to buy the recommended 370 mast for this sail and I simply couldn't believe the difference that the correct mast made. With the 400 mast, the power in the sail was very 'Off" or "On", as the wind varied in its intensity. This On/Off has been completely defeated with the correct mast and the sail is now very similar to all of my other wave sails (which use their correct masts). This difference was apparent the first time I used the mast and I kick myself now, thinking of all of the times I could have had better performance from the sail, but didn't because of the mast cost.
Certainly, having another mast is a pain in terms of cost, but I console myself knowing that, because of the limited usage of this sail, I don't change it as quickly as my other sails, so I expect to have its good performance for a long time.
Hope this helps,