I have been quilting for 27 years and I've always pieced my backs using two seams on each side when I make anything larger than the fabric width. It is so easy with the tube method. I also learned you should never have a seam down the center, especially on a large quilt, because of the stress and pulling on a center seam, if it drapes it will pull on that center seam and will eventually wear out the center seam. The tube solves that problem.