Annie,
Having paid close attention to the exotic fabrics, Odyssey, Top Gun etc, others have been using for junk sails, I decided to use, er, sailcloth.
My decision came about for economic reasons - a firm advertising on eBay was offering Haywards' old stock at an attractive price. Not Sunwing, but a much harder fabric, so much so that I cut myself on an edge. It proved difficult to work with as well. On the positive side, 90 sq metres cost around £400. The seller trades on eBay as englishseadog. Contact by phone for larger quantities: +44 1305 457500.
I am aware that cambered sails place heavy loads on the yards and hope mine are strong enough. Running before a breeze that lifted spray off the crests the other day provided a stern test; no bending of the yards was observed. So far, so good.
Thank you for your kind remarks.
Asmat