thank you, i love rag quilts too. they are the snuggliest. i use batting. cut it one inch smaller all around than the fabric and use 1 inch seam allowance.
i'm getting ready to make one out of denim and will probably use flannel on the back with nothing inside. denim is so heavy. the rag flannel i made with batting is pretty heavy and i figure denim would probably weigh a ton:) would love to hear from someone who has made a rag out of denim.