Hi @Troy.
I think there are criteria by which the relative importance of the elemental movement in a compound movement can be judged. I realize I should have included a brief discussion of the criteria by which I would make such a judgement.
When I speak of a particular movement pattern as driving the picking, my focus is limited entirely to the task of moving the point of the pick up and down through the line of the string.
For this reason, such a movement pattern must be cyclical with it’s frequency exactly half that of the number of notes picked per second. Any other movements which are introduced as necessary, to allow for escaping strokes or string tracking, or any other purpose, are not driving movements.
In Martin Miller’s technique, it doesn’t seem to me that his finger movement occurs on every pick stroke. It seems to me that this movement, while an essential component of his picking technique, is not a driving movement. I’m sure you’ve studied Martin’s technique more closely than I have, so if this is incorrect, please let me know.
It is of course possible that driving movements can achieve more than the alternating up and down cycle.
It seems to me, that most cited examples of players who use finger driven picking are instead using finger movements as required in particular situations. It seems to me that in some cases, finger movement is essentially superfluous.
I don’t believe finger movement is a driving component in Eric Johnson’s playing, as when it appears (which is quite rarely), it does not seem to be cyclical to me. I’m not even sure if Eric’s occasional finger movements serve any useful purpose at all.
Finger movement is more prominent in Yngwie’s playing, but his finger movements don’t look cyclical to me either. I think the finger movements are for string tracking purposes, with the cyclical movement being rotational, as you’ve discussed before.
Omhura is interesting because it seems from the video that @Frylock posted that, at least some of the time, Omhura may be incorporating finger movements as part of the driving cycle. I think there are other situations (as in the video I posted), where the cyclical movement is rotational with finger movement being for tracking purposes.
In both videos, it appears to me that there is always a rotational component to the driving cycle, so I don’t believe that Omhura’s fast picking is ever purely driven by finger movements.
If the cyclical movements are indeed compound movements, there could still be movements which are primary in the sense that they provide the necessary range of motion and the necessary force to push through the string, and secondary movements which do not.
A secondary movement could be present for a number of reasons. It could be a movement which allows pick strokes to escape the plane of the strings, but which is minimal when the escape is not required.
At higher speeds, a secondary movement could be a remnant of a movement which is primary at a lower speed, but does not provide a significant portion of the force to push through the string or range or motion at the higher speed.
It is in this sense that I cannot determine to what degree Omhura’s picking is finger driven. It could be that at higher speeds, the finger movement is providing the power and the rotation is providing range of motion, or vice verse. It could be that both components are essential, or that one is redundant.
If this posit doesn’t convince you, I hope it at least explains my thinking.