You have done a beautiful job. Love the vibrant colors!
Betty Cotton's "Cotton Theory" is a process that is done when it's done. It's a quilt as you go using a some of the open decorative stitches on your machine. There are also other methods of quilt as you go. Also many of the rag quilts are done the same way. But these all involve batting, quilting, and assembly, which is more than the cathedral windows does.