I notice that you say you intend to raffle the quilt at your quilt show. Do you mean that you would only sell tickets at the show? Most of the time, guilds sell tickets throughout the year to bring in more money, and then the winning ticket is drawn at the quilt show. If you only sell tickets at the show, I would recommend spending less money and time on making the quilt, since you will need to at least cover expenses. I've only participated once in making a raffle quilt, and that when I was a very new quilter. One thing I learned is to have extra blocks made, since some of the blocks you receive may not be of the size or quality needed for the quilt top. (They might go on the back, or be used in some other creative way.)