Val Thorens is really, really, really long though. The attacks will probably be more attritional than explosive. Bennett and De Plus could do a job for Kruijswijk. Reichenbach and Gaudu likewise for Pinot. But if Ineos get their shoot together, it will be perfect for them.
OTOH, Iseran is really, really, really high. I have a vague recollection of Thomas coming unstuck at the Tour De Suisse a few years ago when it hit the very high mountains, so that could give him problems.
Also, it definitely won’t be 40° at that altitude, so it might suit Pinot quite nicely.