I have used fleece on the back of baby quilts successfully. You don't need to put any batting in between the top and the fleece. Just be careful not to stretch the fleece when layering it with the top or you might get puckering. If you really want a warm quilt, you might think about using wool batting. It is light in weight but really warm. The issues might be in the washing process. Another idea is to go to your local Salvation Army store and get a washable blanket to use as your batting. Again I have done that and the quilt was very warm, but kind of heavy. Hope these ideas help.