Here’s a couple pictures showing the backing fabric attached to the leaders of the longarm. Two parallel backing fabric edges are pinned to the longarm leaders, rolled up and pulled taut. If the backing fabric is not squared off, it will not load onto the longarm leaders smoothly. I hope these pictures help you understand the importance of proper backing fabric. Pieced backs are great but if they lay wavy and skewed on the floor they will be wavy and skewed on the longarm! For a small fee I will prepare your backing for you or you can purchase wide neutral backing fabric from me. I’d be happy to help you figure the yardage needed for backing fabric, too, just let me know how I can help you!