If I am understanding your original post correctly -
You want to attach the top by stitching only partially through the wadding/batting and do not want the stitches to show on the back
and
you also want to attach the back to the same wadding/batting by only stitching partway through through so the stitches will not show on the front??
If you want two quilted designs, I am thinking it would be almost easier to make two quilts and just stitch through all three layers at one time on each of them.