Oh boy. Unrestricted sailcloth in the main is a real bad idea. My personal experience in laminated sailcloth is that the quality of it is getting WORSE. It really wants to come apart and quickly. Again, when the mylar scrim cloths first came out, they seemed to last a long time, and hold their shape. The current group of laminates seem to be getting worse. PBO was the last sailcloth that seemed to hold up for a length of time. The Hood vectron woven sailcloth looks pretty interesting. I tend to agree with Dave Ullman, who used Dacron mains in the Melges 24 for a LONG time. Dacron tends to give when over powered, helping the boat to remain flat. If you order your main with the top two battens full length, ROLL the sail, do not flake it, and do not allow it to flog, it should last many seasons. (you also should roll a laminated sail.) I also prefer to order the sail with extra bolt rope hanging from the bottom of the luff, and not sewn to the sailcloth. Lots of mains that owners have said are bad have simply had the boltrope shrink. I have taken mains two years old into top competition in the J-24 class and was competitive. Also, remember that if you are racing PHRF with an ODR rating, and you are using a non class legal sail, your ODR rating is invalid. ODR by its definition states that you are racing a class legal boat with class sails.