These will be loaded up shortly; while you're waiting how about having a fondle through your fabrics!
The Spa quilt is only called that because of the fabrics used; in this workshop Valerie selects a range of 5" squares but you could use layer cakes too; simple four patch and rectangles, coupled with rows of squares and then joined with sashing - simple components to create a very versatile quilt.
If you didn't want to use pre-cuts, then you could raid your fabric stash; it would look great as a scrap quilt and in the workshop notes Valerie has included some alternative sizes for you.