Shape - well, I've got another decent chute which I can carry pretty high, so the idea was to get a runner type cut to compliment that (although I might go with an AP instead).
Weight - its Bainbridge AirX 650N, which is what he recommended; from their site: "Specifically designed for classes with a 40gsm minimum weight rule, AIRX-650N has already proven to be a winning fabric in classes such as Melges 24, Soling, J24 and J22."
Boat show discount - good idea. I also just requested a quote from North.