Had a bit of an adventure, I wouldn't recommend the route in "Mud Season" unless all climbers in the party are super confident, there was a lot of loose crap on the the north side of the arete for most of the way. The 4th class stuff on the arete was actually pretty good, there are a couple of pins in place but it could be nice to have a small rack from .4 - 2 camalot or so.
We descended north towards the cabane de tracuit and then took a scree run and glissade down the west face and snowfield, which was very efficient but beware of potential rock fall from the ridge.
There is a good trail towards Zinal the runs parallel to the river so no reason to climb back up to join the trail from the cabane de tracuit.
An easy and confortable ascend as preparation for higher and more difficult enterprises. Excellent weather conditions and very close crevasses at the glacier.
Instead of Bishorn. Reach the summit in severe winter conditions (snow strom).