For your signature blocks on the back be sure and provide Permanent fabric markers. Also you might not want to add the back to the quilt prior to signing because fabric shifts when you try to write on it.
It is usually recommended to iron the fabric to freezer paper prior to signing to make them more stable. also if you do pre-cut blocks - I suggest putting quarter inch tape around the edges to prevent people from signing in the seam allowance. Or if you want to piece the back first (but NOT attached to the top, you could iron freezer paper to the entire back (paper would be in peices).