I used the book Too Cool T-shirt quilt by Andrea T Funk. You can get her book at
http://www.toocooltshirtquilts.com/make-it-yourself/
I really enjoy making this quilt! I've made a few t-shirt quilt all different. I did use interfacing on the back of the shirt. My quilter Likes to have all the shirt Interfacing. I use Joann's fabric .99 cent interfacing it very light. And I add a border. Both things she does not have you do in the book.