Since the pick more or less mirrors the thumbnail with whatever grip you take, not sure how attack smoothness is achieved (no garage spikes) for more pronated or supinated set ups. As it seems USX has much more supination than and DSX has pronation, I’m interested in the USX side of things.
The three finger grip gets the thumbnail off the deviation axis but for index/thumb grips seems like a little forearm rotation is the only option to smooth out the upstroke. Not sure.
Thoughts?