I THINK, the best starting point is going to be to hoist the main and get the mast curve to fit the luff of the main through a combination of diamond wire tension and spreader rake.
I have always wondered about this when people are talking about doing that. Wouldn't you want the curve of the luff to match the curve of the mast only when max downhaul is on? Theoretically, the sail matching the curve of the mast would make the sail as flat as possible, right?
Technically, but the way I understand it is you want the mast to be set up to match the sail such that as you increase down haul, the wrinkles in the luff come out evenly. Spreader rake has effect on this as well. I've also READ that the Tornado and 49er guys don't change this setting much if at all on the same mainsail. I also know our boat was equally fast with a setting of 41 over an 8 month period and many regattas, ranging from super light air to 20-25kts. We are still looking for the mythical 6th gear, but I think its going to come from better driving, mast rake and tension adjustments, foil perfection etc., not from diamond wire tension.
