I have a question that I'm sure I could ask at my LQS, but you know I'm thinking about it right now and it's driving me nuts. I am making the mystery quilt from my LQS. It will be a queen sized quilt. I need to go ahead and buy the backing while it's on sale, but I cannot figure out how much I need. They had told me 8.5 yards, but the fabric I'm looking at is one-way, so I'm assuming I'll need to buy more to make it line up? Anyone want to give me a guess as to how much I'll really need? Thanks in advance!