I would do it like funnyfarm did, seamed on three sides only and left open at the bottom (and not quilted) like lined draperies are made. It will hang better and 'poof' less that way. It will also probably dry faster and be less apt to mildew if air can get in between the layers. Don't forget that the steam from the shower will dampen the fabric even if the actual spray does not. You can get inexpensive tools to put grommets at the top and hang it from the same rings as the vinyl liner.