Lately i expirimeted a lot with different stringtracking movements, which is in my opinion one of the most important things to play complex lines.
Wrist: in this case you will move towards the bridge going from low to high which will give you a totaly different pick angle on the lower and higher strings, unless you compensate with thumb angle.
Elbow: in this case you move slghtly towards the bridge when goin from lowe to high E, which also will give a slightly different pickangle
Shoulder: in this case you can choose to move or slighly towards the neck or more in a straight line.
I have come to the conclusion now that the movement from the shoulder almost in a straight line, maybe slighly towards the neck, is most effective for me.
I hold the pick slightly at an angle and using this movement the angle stays exactly the same on each string.
I believe this is what Martin Miller is doing.
What do you guys think?