Ergonomics

When it comes to genetics the size of the fingers varies between race and so the wave of the key64 keyboard, that will let you make the keyboard to fit your hand size:

Which keycaps to use ?

What about hands placement ?

Webit Says:

I think that last picture is a fail of ergonomic "experts" selling
snake oil, or more accurately, expensive adjustable keyboard trays. In
fact those sculped keys were the result of ergonomics before the word
existed, and designs like the HHKB are made after it, because they view
this design as the ergonomic one. There is no hard science behind
ergonomics, and the older view has as only motivation to make typing
more comfortable, not to sell keyboard trays.

You can see the actual problem in the picture above. With the "right"
design, you have to stretch for the number and function keys. With
sculped keys or an angle, you don't.

Their reasoning is: with a flat angle, you don't have to bend your
wrists!

But that is simply wrong. Don't take my word, do
this experiment: Place your fingers on the home row of a keyboard with
an increasing angle. Move one index finger up to hit a function key.
You don't bend your wrist, it just decreases the travel for the finger.
This is because you lift your finger to make the movement. The wrist is
not involved at all. Now do the same on a keyboard like in the "right"
picture. Wrists stay the same too, but the function key is harder to
reach.

It is simply not true that the angle of the keys determines the angle
of your wrists. The height of the desk + height to the home row of the
keyboard is what determines this. And your habits.