I agree with the GTG aspect, but not the sitting at your desk or in the car bit.My opinion the grip is best worked GTG style.
Just keep a grip ring or ball of putty or wax in your jacket pocket or on your desk/workstation/vehicle dash and hit a bunch of reps and static holds throughout the day.
You can also do GTG sets of 100 rapid air grabs - basically open and close your hand as fast as possible 100 reps - tougher than it sounds.
Makes sense. I don't use grip for much of anything outside of climbing, so I can possibly focus more on climbing-centric grip skills.Fair enough. I use grip outside of the gym so too much of the super specific work puts my recovery abilities over the edge. The drills you exclude are what help me stay balanced.