Sail Panel Layout

I believe creases/wrinkles are common when a sail is tensioned beyond (or below) its design limits and the limits of adjustment are exceeded. Sailcloth with more stretch will accommodate a wider range of adjustment/shape but will hold it's shape less well under load and will have sub standard high wind performance. A low stretch cloth will make a sail which keeps it's shape better under load but will have less range of adjustment and be 'stiffer' and harder to read in light winds. Under load the aim is to allow gust response but keep the CoE reasonably constant so the sail spills in the gusts without unduly moving the CoE. Floppy head designs in windsurfing which set on downhaul alone are a perfect example but they tend to be slow in lighter winds. Dinghies have and significantly more sophisticated rig controls so can cope with a wider range of wind speeds with a single sail so the dinghy equivalent is a bendy mast and lots of cunningham.