The local Doyle sail maker got back to me today with some verbiage to use:

The Main shall have a minimum weight of *_____*, excluding battens. The intent of the rule is that all sails submitted for measurement will be constructed using well establish sailmaking techniques. The class reserves the right to reject any sail with additional weight added to the sail that is determined to be there for the sole purpose of meeting the minimum weight.

So far my sail maker, Dieball Sails, has offered a recommendation of using 9-10kg as the minimum weight. Over the weekend, I'll pull my old sails (1 Dacron + 2 old string sails) out of the attic and weigh them and report back.

Does anyone have contact with a North Sail Loft that could offer input on the weight of a 3DL main?

I'd be happy with a rules change that allows string sails so there's no push from me on changing battens. That said, one sail maker suggested it - any thoughts on allowing 5 battens? Or, should I leave this one alone?