The last post on this thread was over 6 years ago, but I enjoyed reading it again from the beginning. Although I no longer own a J/30 (moved to a J/109), thought it appropriate to stir the pot again. Sail technology has changed over the past 6 years. High tech sails are no longer laminated. This discussion / evaluation may want to be resurrected since now there is a process using thermoset resins that don't delaminate. The acquisition costs have come down and the longevity is far superior to laminated sails (e,g, mylar / string).
Any thoughts from J/30 owners if alternative materials should be reconsidered for the main?