I make a lot of memory quilts out of loved ones clothing. They are not all cotton or the same thickness of fabric. I put backing on the thinner fabrics & they turn out fantastic. I don't limit myself to just one fabric. I use just about everything in these types of quilts. Some quilts I will use all cotton or all poly/cotton blend, but not always. It is what you prefer to use. Just don't let the quilt police know. :~) All is fare in love (sew) & war (quilt).