Im not going to pretend to be a shredder, in fact, I'm probably a little slower than you. However, I will impart the beliefs I have gained. The less you move you arm, the more efficiently you can play the guitar. Moving your whole forearm is a waste of movement when you only want to move such a tiny distnce. I tend to use my wrist only, which is better, but I know that some shredders just use their fingers, using a circular picking technique. Anyone care to elaborate on this technique?