The #1 question about grip that I get in class is "How Much Does Each Hand do?".
Over the years I've heard many answers to that question from instructors I've had courses with and also from students and other shooters.
We take a more specific purpose driven approach to thinking about this.
I usually answer with a question... "what is your trigger hands primary job"... Answer... uhhmmm pull the trigger. "And your support hands?" Answer... Uhhmmm... support??".
Right! So in a nutshell... how much grip pressure you do with your support hand? As much as you can. It has no other duty (except for helping with sight alignment and that is done with the wrist and arms). So do as much as it can! Want to do more? Excercise it with Captain Crush grip strengtheners or similar tools.
That leaves the trigger hand... here we need to be more nuanced. Its job is to release the shot without disturbing the gun more than is acceptable AND to get that trigger reset during recoil and return.
To do that you need a bit more flexibility. So do 100% of what it can do without hurting your trigger pull or your ability to reset the trigger.
Want it to do more? Captain Crush again... but more importantly learn to grip from front to back through the middle knuckles so that your trigger finger isn't as connected to what your hand is doing. I'll do a video on that soon.