2 liters/person are not enough if the hut on the top is not opened!!!
Funny, not very hard via ferrata in sunny day, long descent..
30°C, 3 liters for the ascend and one for the descend via Sarche, more than 10 hours from car to car, but it was a really great tour. It's absolutely worthwhile the effort - the views to Brenta and Adamello reward for every pearl of sweat ;o)
4 liters and a 6 am start just about got two of us through the August sun on this climb. Thanks to Nigel for the beta. A few comments: the hardest bit is the "preliminary" section before Che Guevara officially begins; Che himself is entirely mellow. The hiking above the finish is a delight, especially the shady bits. And trail 426 is "chiuso" in 2009; but most will, like us, prefer descending 427 down the shady north side of the peak. This is a good trail but one has to watch carefully, as it repeatedly runs with various forest roads and then makes poorly marked divergences.
Thankfully, the day was mostly overcast. Even so, a few more litres of water would have been great! A long day out.