I also think it could be your batting. I quilt all the time using stitch in the ditch and I find the poly batts definately pucker more than a cotton batt or a cotton/poly batt. No matter how I pin, baste or pull my fabric taut, I can't get my quilt as flat and as pucker free with the poly batt. It always has that slightly puffy look which is fine for many quilts but it may not be the look you want for your daughter's special wedding quilt. The walking foot will help but will probably not completely eliminate the slight puckering if you are using a 100% polyester batt.