I just had my first little tuck. What did I do differently? - sandwiched that one in a hurry. I use the Sharon Schamber method with the boards and have had very smooth backs, but I did the nursing home quilt in a rush and in the company of others so I must not have paid as much attention. Previously I used 8 top tables put together. I never had a problem but I used a lot of tape to hold the backing in place until it was pinned. Can you release some of the tension on your presser foot to accommodate the thickness of the quilt when doing the straight stitching with the walking foot? I can with all my machines except the Elna.