About 12 hours into the day, descending toward Denali Pass. I took our second team of guys to the summit from 14,000’ in a 15hrs 30min roundtrip. Despite it being a big day, I think this is the best way to climb via the West Buttress: hang out at 14k for a few days, take day trips with a light pack to 16k and 17k, rest well, then punch for the top. One avoids carrying a huge load to 17k and sleeping there, where recovery isn’t on the menu, only deterioration. Starting fresh and hitting the top from 14k carrying a day pack is no harder than starting wasted from 17k. One may need a bit better fitness, and certainly the discipline to pay attention for 15 to 20 hours straight, and the sense to take care of hydration and nutrition throughout the day. Still, it ain't easy ...