you are going to have to quilt the backing too so it stays attached and doesn't bag. you can either sandwich the 3 layers and then quilt as a single unit, or you can do some type of quilt as you go (QAYG) where you actually use bat & back and quilt a block or section and then attach them together as a whole. Both have some advantages, the QAYG is more manageable but you do have to deal with the sashings or other ways to attach and either have a seam on the back, or you have an area that you manuver together--check out youtube for these ideas. and if you quilt it as a whole unit, it's bulky in the DSM, but not impossible.