Just signed up to say I really appreciated you taking the time to make this video, was very useful.
Might be a bit late but I stumbled across this page when looking at grip types, I've been an avid gamer (pro once before I got older and lazier) for over 15-20 years (if you can count the old classics like Doom without mouse look and further back to Commodore 64's and Spectrums) and I've never even known there were actual grip types, I've used all of them depending on the mouse I had at the time.
Have a non healed break in my wrist at the moment that cannot be rectified any time soon so am now using a fingertip grip on a Cyborg R.A.T. 9 (great mouse but the back and forward buttons are terrible, wore them out in less than year, heavy usage mind you) to the point where one snapped off, currently seeking an RMA, looking at trying a Naga epic for MMO usage and sticking with a hopefully replaced R.A.T. 9 for FPS.