Very interesting, never heard this before. It makes sense.
Unfortunately (for me anyway) the biomechanics of my hand shift slightly to a more vertical 'grip' angle when I open up from a clenched fist to an actual shooting position.
You can easily experiment for yourself, extend your clenched hand, then simply open it up as if holding a gun. You will see the angle of your grip palm change slightly upwards.
At least mine does. It is why I never really could get used to the Glock angle when shooting (shot G19 and G17 rentals at the range.)
Not Glock-bashing; mind, they just didn't work for me.
The back straps on Gen 4 guns solve the grip angle issue.
