So I've decided to do a commercial rating, er, certificate. Not because I plan to fly commercially... there are so many other benefits (required reading, studying, maneuvers, etc etc). Keeps me fresh, adds experience, and dammit I just love flying. I have instrument rating. Seems like there's a bit of overlap on the knowledge / written stuff. So my question: what course materials would you all recommend? I just purchased King online (used them for PPL and Instrument). I have the ASA iOS app as well. What am I missing?