I am getting ready to take a class using the lucky stars pattern. The pattern calls for yardage for the background, binding and backing. Clearly from the picture, there are several fabrics for the background. I have no idea how much and how many colors to buy. I do have a nice bolt of white muslin to use as backgrounds for the stars. What do you do? I want to shop JoAnn's sale this weekend. Here is a link to the pattern.