No... it's always personal preference. You can piece it either horizontally or vertically. I have also seen people use their bigger leftovers from the top for the back. I would consider piecing horizontally. You want 3-4" around all 4 edges of batting and backing. So your backing should be length 70-72" and width of 58-60". Also, feel free to ask at your local quilt shop when you buy the backing.