In fact, the Magic Mouse seems to be almost antithetical to everything I've been taught about mouse ergnomics
I line up the armrest of my chair with the top of the desk so they're a level surface. I adjust the height of my chair so my arm is at a 90 degree angle. My arm runs flat across the arm rest and the desk, and my palm sits on the flat mouse pad. Then, I just move my finger tips to flick the mouse 1cm in any direction for getting to different sides of the screen.
For keyboards it's similar. I use a thin and flat keyboard. This way my elbow (on the armrest), forearm, palm, and finger tips are all in a straight line. If I add any type of wrist rest, then the weight all goes to the wrist instead of being distributed.
Lastly, I dislike keyboards and laptops that raise the backside because they raise my finger tips and put pressure on my wrist. It feels much more natural for the fingers to be lower or equal to the wrist and palm.
Anyway, just my experience. I had some discomfort for a few years, and then nothing for the past decade.
Did you ever get a chance to try a vertical ergonomic mouse? They take a while to get used to, but the idea is that you don't rotate your wrist (i.e your ulna and radius remain parallel) and keep it in a more neutral orientation.
Theoretically the best wrist “rest” in this scenario would be a bed of sharp nails..
If your palm lays flat on the desk and your wrist is at an upward angle, that'll hurt your tendons pretty fast and affect your fingers and wrist. The wrist pad doesn't help a lot though because if you move the mouse with your fingers you'll have to grip the mouse more tightly rather than just rwst your hand on it and move it around by moving your forearm.
Ideally your hand would be slightly rotated so that your pinky is closer to the desk and your thumb higher up and if you need something to elevate your hand, then the pad would be closer to your elbow so that you can use your forearm.
Those people injured their tendons and now cover it with their wrist, other people will have other issues, with other workarounds.
If you mean regarding to heights, distances, etc, yes.
Else, Err, not really. Anatomy is anatomy, people don't have different design of hands, wrists, etc.
Even for the targeted morphology, if you exactly stick to the recommended posture and input device etc. for 8h a day whole week, you will have issues anyway, it will just be a matter of what hurts first.
The consensus as far as I know is to rotate posture (e.g. sitting/standing), input devices if possible, and try to avoid repetitive actions on always the same body parts.
"It is absent in about 14 percent of the population"