Doesn’t matter how you choose to pick fast. Play fast. I’ve noticed that you gotta figure out some way to make the pick glide through the strings on both the downstroke and the upstroke. Like a knife through butter.
Picking from the wrist I have serious doubts about. It doesn’t seem to work very well. I have more success with picking from the thumb and forefinger like Yngwie does it.
But I still have problems with getting that pick to just glide through the strings without unnecessary resistance when picking. You have to figure out some way to minimize resistance or you will never play fast.
Some people can do it and some can’t. I’m beginning to believe I simply can’t do it.