Just from my experience, I would try to do more than 1 if you can. I only did one, and I now regret it. I matched, and I am happy with where I matched, but it was not my number one choice. I am similar to you (not AOA, average step I), and I really feel like my app would have been much stronger with another letter from some stud at a high powered program. One thing I have learned from this process is that the most powerful weapon in your arsenal is the away rotation. Your goal in the next year is to not let yourself be limited in any way, and while doing only one away will not condemn you to scramble/prelim/research, it certainly could limit your competitiveness at some programs. Try as hard as you can to do two, work your tail off when you go, and make sure that you get a good letter out of each experience.