i know you don't want to be left with pre-cuts if you don't sell them all. do you expect to be invited to speak elsewhere? if so, you can sell them there as well.
the only other thing you can try is a line that has a lot of parts. bring samples and take discounted orders. you might sell one-yard or 1/2 yard pre-cuts of those so people can feel them. show all the color possibilities and take the orders, don't forget the deposits. the guild may also want to discount-buy an entire bolt of something for a challenge, with members then buying yardage of their choice that goes with it. they can buy the choices from you on order. maybe you can suggest some patterns for this project.