I have been trying to speedpick for a while now, and I usually pick using only my wrist (sometimes minimal arm movement) with the pick angled (I could never get far past 90 bpm with 16th notes), but my new teacher told me to use more arm movement up to the elbow, keeping the wrist more or less stationary in relation to the rest of my arm, and to try the pick flat against the string. I can play faster, but less evenly, with less control, and my elbow gets stiff.
I tried watching videos of shredders, including you and Kristofer, along with Rusty Cooley, Paul Gilbert and Michael Angelo Batio, but I am confused as to how to approach all of this.
I would really appreciate help. Thanks