From the hut descend to the main glacier below. Skin very gently to the NW up the long FIescher Glacier, heading for the R hand side of the icefall at the head of the glacier. Pick a line through the crevasses, watching for the seracs far above you. In a good season you may be able to skin up through the crevasses further L, thereby almost entirely avoiding the serac fall danger above. The upper part of the glacier is also easy angled, taking you towards the col in between the 2 Fiescherhorns. You can go up these in either order, possibly slightly quicker to skin up the Hinter, then you can ski down to the base of the Gross. The route is marked in the other sense, as the Gross is the major summit with more technical ground and a better view. Allow 45 mins to the summit and half an hour down. It is mixed scrambling, the first part getting onto the ridge the hardest bit. An in situ rappel point may be in situ there for the descent. From there a short snowy descent allows a straightforward ascent to the summit of the Hinter. Descent to the hut is straightforward, following your line of ascent.