help/problem with new sail
Leech flutter can come from a lot of sources but in a new sail, it sounds like a problem with the cut of the sail or the jib sheet lead. When you say that the jib sheet leads are set in the proper position, has the lead been been set so that all three sets of teletales are flying at the same time? If that is the case and you still have leech flutter then there probably is a cutting problem. They will need to reshape the leech area of the sail. There is one other possible source of the flutter. If the sunscreen material is too heavy or installed improperly, it will often create an assymetry that will cause a leech flutter no matter how the sail is cut.
Its funny,I hear about these kinds of issues much more frequently with mail order sails. I suspect that with locally purchased sails, buyers are used to getting the sailmaker to sail with them and observe the new sail flying and then make a set of final adjustments to the sail shape. That used to be the expected norm. Of course you can''t do that with a mail order sailmaker.