Paul,

I would debate the benfit of adjustable tensioners during a race, mainly becuase it is just 1 more thing to worry about and distract you from actualy sailing. Some of the A cat guys swear by them but mainly as a quick rigging adjustment if the wind speed changes drastically between races when you are out all day. It may be a cool device to use to test sails though to find that median sweet spot.

The new big head sails need stiff masts. The A guys are really finding that out, gone are the days of tuned masts for sailors weight. As Hans pointed out the Aluminum mast is not nearly as stiff as the new carbon ones. Everything you can do to stiffen it up seems to be quicker. The Taipan class rules were 700mm spread. We started here and I am now using arms that are about 10.5cm longer than the Taipan length spreader arms and it seems to really help. The top of the mast is where you then have to really concentrate to keep the rotation in tune with what shape you are trying to keep in your sail. Just a slight bit too much rotation and the top of your sail will go board flat AND not twist off. We only over downhaul in the very light stuff (when the crew has to go leeward)for a flat sail. As soon as we can almost both sit on the same side I am filling up the pocket with more rotation, less down haul and a slightly looser sheet. Keep that smooth transition of the mast and sail luff you mentioned at all times up wind.