I want to sew the binding to the back, fold over and sew it down with a decorative stitch. But what I don't understand: if I want to "fill" the binding with 1/4" of batting and trim the batting 1/4" from the edge of the quilt, do I sew the binding to the back at 1/4" DOWN from the edge of the batting? Isn't that hard because it won't always be an exact 1/4"??