My friend and I plan to do this hike in the early morning end of November. We are both quite fit and do hiking on a regular basis. We need to be at El Calafate airport around 5pm (for 6.25pm flight and return a car), so we plan to leave El Chalten around 2pm by car. What time should we start the hike? Is 6am early enough? It gives us 6hrs for a hike (round trip). Any advice is appreciated.