about where and how they sign the blocks: I'm a custom picture framer and we get a lot of orders of "signature mats" from a wedding. Yes, people tend to sign alllllll the way to the edge (kids sign their art at the very bottom edge, too. It must be human nature.) Anyway, for the siggy blocks, try drawing a pencil line of what will be just inside the seam allowance AND displaying a block of the "ideal" signature. People will copy what they see.