I belong to a Quilt Guild. This spring John Flynn taught a class. It was his Red Hawk quilt. He had us bring a small (I think the 18mm, but not sure) rotary cutter. He included a heavy acrylic template for cutting the points of the arc (it is similar to a New York Beauty). If we tried to use a large (45mm) to make those tight curves, it wouldn't go. The smaller cutter was perfect for following those small curves. Oh, and by the way, if anyone has a chance to take one of his classes - go for it! He was great.