Originally Posted by
DrIsotope
The adjuster on the back of his helmet looks to be all the way out-- like his head is at the intersection of S/M and M/L, so he wears the smaller size opened all the way up, presumably to save a few grams. The Vertigo and Protone do seem to sit closer to the ears. My Vertigo 2.0 does, for sure.
I just bought a Bontrager Ballista sized small because I was between that and medium, and it ends up sitting slightly too high over my temples like OP is worrying about with his helmet, though in my case it's because my head is wider than it is deep. I think the medium size would be too big though, so I'm fine dealing with the helmet otherwise.