Just an FYI – when choosing a backing a couple of things come into play, are you going to have it quilted or tie it, if you choose to tie it a sheet is acceptable, if you choose to have it quilted, quilters prefer you use a material. The reason is sheets are usually of a smaller thread woven tighter where material is larger threads not as tightly woven, thus fewer pulled threads and it doesn’t dull a quilters needle as fast.