Ok, i see that you are quite informe on the place...
I don't go there much any more, 4 snowkiting, has every time i went it was a kind of a mission, and that wee have really good snowkite spots up the valley.
It's really hard to "understand what the wind will do in that area, and when there is too much the top télecabinne is closed, so wee kind of stop the kite exploring up there.
But when wee did try to find spot's in that area, wee kited a few time in col du midi with verry light wind coming from italy side (S_E) and N and they where ok... I allways wanted to kite in the Italy side (S-E) by the hold ski lift but never did at the end (i think you could access lot's of good free-ride back into vallée blanche...).
The day wee went up the end of vallée blanche to the Vallée noir was a lucky day, Top telecabinne closed with srtong north wind, and a friend and i dicided to go up with the train to see if it was possible, it was not a really enjoying day, it was hard but wee made it to the split and a litel more into vallee noir, but the all thing was a workout...
I spent all my life in Cham, was on of the 1st snowboarder there, and this place use to be my playground 4 free-riding and i know it quite well, and it's a fact that that area is full of danger and lot's of people died there every year, every time wee went there wee keep clear of all those danger, huge drops, crevasses, seracs, storms...