This is going to be a lovely wedding memory quilt. I would however suggest that you do go ahead and have a wedding book as well for the guests to sign. The reason being is that their names will then be in the book as well as on the quilt. By having the book as most people are used to signing you can determine if someone has missed signing a block and can add their names in printed format so that they're included in the names on the quilt. Just a thought...to think about. Wedding books are reasonable in price. Your daughter will thank you many years down the road for having both even though she thinks now she doesn't want it.
Pam M