More info for DougsterDoc as my morning coffee kicks in. I was sifting around and found this statement on QB. The lady has a Singer 15-91 and she stated that for quilting a quilt with a polyester batt she uses these settings: A universal needle 90/14, 30 weight thread, top thread tension at 7, and bottom tension at one o'clock. We know you're not "quilting" but maybe these settings can get you in the ballpark.