Watch Design Wind Speed
Sails are not cheap and you don't want to buy them any more than you have to.The reason sails loose their shape is through both constant use and being over stressed. This is akin to battery life and the years of use and the number of deep cycles. The battery will eventually wear out even though it never had many deep cycles (a.k.a. 50-percent discharge) and somewhat similarly with sails. As deep cycles take their toll on batteries so does overstressing on the sails. Therefore, one should be careful about flying the sail in conditions beyond their design strength. A couple options are as follows. For a given wind condition there is an optimum sail configuration for the boat, say full main and 110 jib at 18 knots. The wind pipes up to 22 apparent and the smaller blade needs to go up and a reef in the main. If the smaller and heavier jib doesn't go on then the 110 gets overstressed, a deep-cycle.The other option is to get the 110 made with the next heavier weight fabric. This has it's drawbacks in lighter winds but if you want to push past the point with the gusty winds or it's just a little bit further to the mark you can leave it up, pinch a bit, and go with minimal damage to the sail. Cost for the heavier option is very little over the total price for the sail.The good part of a heavier sail is fewer sail changes, it will last longer, and keep a nicer shape longer but the downside is it's harder to handle with sail changes, the fabric isn't as subtle, and there is a bit more weight aloft.The sailmaker should give you apparent wind speeds for your sail and then you job is to stay within that range. Going beyond will damage the sail and it's shape.Something else to consider, and this may be part of your question, is that some fabrics tend to be more suited to over stress. Dacron tends just to stretch where as the laminates tend to come apart. Knowing how the paticular sail fabric will destruct will affect how you want to handle a particular wind situation. Because time is money, finding a sailmaker that will take the time to explain everything is tough.