there are many weights of muslins- just because it is heavier than what you've experienced doesn't mean thats not what it is- but it could be feedsack's too - either way it's a muslin
backing it with a nice quality muslin would be nice- you could use white or natural
the fabrics are vintage 30's-40's fabrics
if you wanted to use a print for the backing instead of a solid-or muslin you could pick up a repo 30's fabric that goes nicely with it-
connecting threads have some nice ones for very reasonable prices.
great find- can't wait to see pics of it finished
