I use flannel as batting. It is easy to find (thrifted) or old odds and ends at home. The texture also seems to help it "cling" to the quilt top, even with lots of transporting as with all my hand stitched projects. I still pin the layers, but minimally really. I do a lot of my hand stitching on just two layers, top and flannel. Then, I add the back layer and machine quilt the three layers together, hiding my hand stitching thread ends between them.
I am going to try multiple flannel layers in some areas on this project, to add a bit more relief to the positive spaces. I have cut away the negative space flannel and now the back has a interesting look on its own, a bit of raw edge appliqué. I will add another layer of flannel, so positive areas will have two layers of the flannel rather than just one.