My longarmer doesn't care which way the seams are. I've even given her quilts that I had pieced the backing together. She's never said anything to me about it. Perhaps the longarmers need the income and will quilt what ever we send them. Several ladies in my quilt club are making a ton of scrappy quilts to use up scraps and not buying fabric. Many of us piece the backings and have never had a longarmer reject them.