In reply to Mike Lewis: Interesting, thanks. I was under the impression that bivvy hut is 15mins from the start of climbing, while from the hut it's more like 1.5h - 2hrs. But perhaps it's not worth the hassle with melting snow for water, carrying the jetboil, sleeping bags etc. Guardian from the hut told me the same when I called to make a reservation, i.e. south ridge normally done from the hut not the bivvy shelter.
How long do people normally take on the route?