Large simple quilts I do this way. I simply divide top, batting and back into three sections the whole length of the quilt leaving 1/4-1/2 seam to be joined to the next section. Then I machine stitch the seam together on the top layer. Tuck in the batting, turn over to hand stitch the backing by leaving one part of the seam flat and turning over the other part over that. Clear as mud? Silvia