since theirs a bailout at the halfway you can get away with one rope but ya gotta bring crampons? for that. also depends how versed you are in down climbing and how much over-all risk your willing to take. other than that, one rope is fine. unless someone gets hurt and it starts raining, then your going to wish to god you had two ropes, but theirs so much pro on that climb you could build anchors anywhere and eat your rack. of course this is the long winded version