I used Hobb's Tuscany 100% wool batting. I'm relatively new to long arming, and I should have tried a quilting a sample, however I had no extra fabric or batting to experiment with. I have been told to set the bobbin tension by holding the bobbin flat on your palm and pulling up with the thread. The bobbin should stand up in your hand, but not lift off your palm. Then set the upper tension. The quilting on the back looks like the bobbin tension was too tight or the upper tension too loose.