More or less, it's all relative to what you are trying to get the disc to do. The main thing is to keep your arm on the same plane with your shoulders. Rolling your wrist under will cause hyzer and over will cause anhyzer, perpendicular is where you'd want it for a flat throw. For visual reference, check how homeboy's shoulders are aligned with his arm; you'll notice that he's rolled his wrist under a bit which has given the disc a bit of hyzer.
It's a big picture so I'm hyperlinking to it: Pic of dude's drive
It's a big picture so I'm hyperlinking to it: Pic of dude's drive