I would stick with a natural fiber - cotton; wool; silk. Silk is really pricey and unless this is to an 'heirloom' quilt not sure that I would spend the $$ for that. I, too, use W&N exclusively (I bought a roll!) so I understand the 'stiffness' to which you refer. I've not used it but my quilty friend uses Quilter's Dream 100% cotton and it has a great drape to it and very soft. If you have somewhere local that carries that could you possibly go fondle and see if that would work for you? Otherwise I would probably go with wool or the extra layer of flannel/flannette that others have suggested.