There are so many variables when you stitch together two layers of fabric and batting that I think it wise to always make a scrap sandwich and try out the stitching, needle, tension and thread before starting on the quilt itself. You don't have to rip out on the scrap sandwich. I keep a little notebook to record my successful combinations. My favorite combination and used most often is Bottom line thread to STID; King Tut (40 weight) to do quilt design work; 50 weight cotton in the bobbin; and, size 14/90 topstitch needle.