OK, I'll take a stab. No experience, but based on an educated guess. The thing that determines how closely you quilt is the batting. If you use no batting, you might be OK. If you use batting under the strips, check the package. Don't know how many layers you will have, but 15" is a long way. I would think a wiggly serpentine down the center of the strips or an elongated X would not go amiss.