I also use freezer paper ironed shiny side toward the fabric on my signature quilts. They iron on easily and remove easily as well. I went to Hobby Lobby and had a picture frame mat made that I could tape the quilt blocks to the back of and had them make the mats to cover 3/8" all the way around the blocks so I didn't have to worry about the seam allowance being written in. I can re-use the mats for the next signature quilt I make. I also used Pigma Pens for the guests to use to write on the blocks - do make sure you heat-set the ink with your iron before putting the quilt together and don't use steam!!! Dry iron only.
Good luck with your autograph quilt. I have made several of the (7 kids) and they are a great way to remember any special event!