With or without the cornerstone stars, IMHO, Polly has the right idea. You may not need that many filler blocks. The ones I've made only needed one after page 2 and one before the last page. Do a layout and see what looks good to you. Unless the book fabric is terribly flimsy, it should not need any special backing to strengthen it. If it does, selectlight weight iron on interfacing.
PS. Generally quilters love to help. Don't get in a twist about asking. I'd have become a competant quilter much faster if I had been ready to ask for help.