I love the 9degree wedge ruler it is so much fun. I've made spiral quilts, table toppers, butterfly quilts, and butterfly wall hangings. I think it would be worth your time and money. I also took a class, but I think you could probably learn it yourself, there is a book out I think it is called quilts without corners, it is a good book, and explains very well.
You can do all kinds of different things with the ruler, I used it to make a bargello type quilt, by turning the ruler 180 degrees, and sewing them into a straight stratta. It turned out really neat.