when I am using my floor to layout a 'sandwich' i'm going to be fusing I usually start with a piece of flannel, or a different (non-fusible) batting- then lay out my backing, batting, top. as for the 'stiffness' it should wash away- since the fusible will wash away when the quilt is laundered. I've not tried 'Fairfield' fusible batting- but the fusible battings I have used all softened up-washed away when laundered. as long as it is not a 'craft' fusible made for projects that will be stiff & not laundered. reading the package should tell you what to expect.