The way I do mine is probably unacceptable by the Quilt Police but it works for me. I quilt all my blocks individually with just the block & batting--no backing. After the blocks are all quilted, I add the sashing between the blocks and join them together to make the top. I then use one piece for my backing, spray basting the quilted top to the backing. I then quilt all the sashing strips. This attached the backing to the quilt top. When you look at my quilt from the back the only quilting you see is what's been done in the sashing. I've done this with different size blocks from 6" to 12" and I've had no problems with the batting shifting or anything.