Rolling the ankles (i.e. inversion/eversion
is important for good skiing and as mentioned before, the boots must be tight to transmit those movements, but without restricting those movements too much.
While we all focus on tipping both, some focus on the inside foot tipping more and some on the outside... The OP I think is asking specifically about the eversion, i.e. tipping the outside foot towards the inside of the foot, i.e. lifting the pinkie. That's what we do with the outside foot. And specifically, the question is using eversion to increase the angles, so that implies sort of the bottom of the arc.
I think there is some element of that, for sure, I mean I think if you strongly evert when the ski is already on edge, it probably helps increase the angles a bit - it was also my focus at some point. I know some coaches talk about that "pedalling movement" or such. In my mind it is not very effective because at the end of the turn, you are ... uhh... bracing?... against the stacked outside leg and your foot eversion works against that, by trying to lift the heel even more and push your hips further inside the turn.
At the same time, that foot is certainly everted at that point, to maintain alignment and keep it on edge, and eversion is a small range of movement (compared to inversion) so I don't know how much more you can evert it - you can probably increase not the range of movement, but the effort.
In my mind, eversion is more effective in the beginning of the turn, complementing the extension of the outside leg to maintain snow contact.
cheers