It may sound easier to sew inner border to outer border and then sew the piece to the quilt, but then you have to miter the corners! I hate mitering corners so I do the "extra work " of sewing each border seperately on to the top. Really is not that much work since you are still sewing 2 seams. No need to miter corners then unless you are a "glutton for punishment" Actually I just sew each border like I would any border. If you fabric "demands" to be matched, then make a "HST cornerstone" of the outside fabric and insert it using the usual method of adding cornerstones to borders! After quilting you really cannot see the extra seams!