The only other additional training that I do is martial arts one day a week. I used to own a grappling/mma gym that I ran for about ten years. I closed the school a few years ago but the friend that is still training CC comes over once a week and we train boxing/submission grappling for about an hour. I figure that way I won't forget how to do some of the stuff that I spent the better part of twenty years learning and my friend is a prison guard who needs the training to keep from getting beaten up at work.
I'd say that the results that I've seen have to do with the variety of exercises in YAYOG as I saw similar results the first time that I did the routine. I don't know what it is about the workout but my wife commented that when I do YAYOG that my arms, particularly my biceps, seem to blow up and get visibly larger. I'm sure that the reason that my shoulders have gotten larger/more well rounded has to do with the upward pressing exercises like the military press and dive bomber pushups. When I was doing CC I hadn't gotten to step 6 in the push ups and pull ups so I hadn't yet started on the handstand pushup work which would have eventually addressed that.
Don't get me wrong I liked the CC workout, the time spent on it certainly wasn't wasted. I'm not suggesting that I didn't get good results from it.