You really want the least amount of seams on the backing. Remember, you have all the seams on your top and sometimes when quilting if a top seam and a back seam met, you might have trouble with the stitching because of the bulk. Also, the more seams the less fabric you have to work with. If you should ever catch the PBS show Quilt in a Day (also on the RFD), one of EB assistant is Sue Bouchard who ALWAYS uses up all her leftovers for piecing the back of her quilts. EB will always show the backs of Sue's quilts on the TV show.