Yup, that's how to do it - and that's why we do. That bookcase gave you the perfect inspiration in your sewing room. How much to buy really depends on you and your budget. I'm a very scrappy girl. Rarely buy more than half a yard at a time - unless it's a remnant or I need borders or focus fabric. Looks like you are into scrappy from your project. Have fun! with this crazy obsession.