Don't overlook the 13 and 15 inch mid arm machines. When a large quilt is rolled in the bed of your machine, it reduces your quilting space. A 9 inch arm can be reduced to 4 inches, while a 13 inch can still quilt 9 or 10 inches depending on the thickness of the batting and how tightly it is rolled )and the 15 accordingly. The more quilting space you have, the larger design you can use.