A book that helped me a ton was "Why am I still depressed?" by Jim Phelps. Others on here have mentioned liking the book too. Very informative about BP II. I definitely had several ah-ha moments where I saw myself in the book and realized how well the diagnosis fits. It also has info like you are looking for, like things that are correlated with BP II that aren't part of the official criteria but may be clues (e.g., age of onset, reaction to certain meds, etc.)

Good luck,
EJ