Incredible tour which I fully recommend doing. It took me from the Hungerbrug to the top 3:20, so I feel the numbers in the description are a bit conservative. Which was a good thing, because you will walking in the sun nearly the whole time. As stated, the last 300m is intense and in the alpine region, falling here will result in a long tumble, for which you are rewarded with a great sight of Innsbruck and the Inntal. Water can be refilled at the Achselbodenhütte and when I did the tour that was the last opportunity until Gasthof Rauschbrünnen (i.e. no small streams, will be probably be different earlier in the year)
I saw some people continue to the Vordere Brandjochspitze, which looked like 2nd class (UIAA) terrain, so for experienced mountaineers this may be an option.
As a warning, the GPS track is nearly spot on until you come across a Forstweg after the Rauschbrünnen. Instead of going straight down (as the GPS track does, which seems impossible), you have to go to the right (west) a few hundred meters and then there are some signs again.
Grandiose Tiefblicke auf InnsbruckDetails