I think the wind-up is almost as important as the strength of the shot, maybe even more so. Usually, wind-ups that take a lot of time aren't particularly effective. Although Salo was pretty good at that, but I think that had more to do with opposing players being scared s***less about his shot than anything .. they usually got out of the way if anything (for the few players who dove to block his shot, I'm not sure which is more true: whether they were brave or just plain stupid ).
Garrison, otoh, clearly has a faster wind-up. He may never be the PP specialist Salo was, but I think he'd be better suited for quick one-timed shots than most in the league, and that's a nice asset to have, if true.