I am self taught and I am thankful for this thread. I have always trimmed of my extra batting and backing before I sew the binding on. I will now try the other way. When I do cut the extra off I have been leaving about 1/8 of an inch more because it seams to fill the binding better. My binding is always 2 and 1/2 folded in half and pressed. I square up my blocks as I go or before I sew them together. I would square up the entire quilt if it needed to be.