Howdy
I ALWAYS curl my pinky under the grip. Trying to cram my entire hand onto the grip, even with an 'original model' Vaquero, results in my middle finger being too close to the trigger guard, and getting whacked in recoil. Curling my pinky under the grip allows me to leave about 1/4" between my knuckle and the trigger guard, which is good insurance against getting whacked, even with full powder Black Powder loads. I do not hold the pistol with a death grip, I actually hold it rather lightly. The gun recoils naturally, with the muzzle flipping up a bit, and my pinky arrests it's motion, translating the recoil into a slight upward motion of my entire arm. This does not hurt my pinky one bit, it works just fine. I usually hold Double Action revolvers the same way.
The only exception is my 1860 Armys. Their grips are just too long for me to curl my pinky under and still reach the hammer spur with my thumb. I do cram my entire hand onto the grip of an 1860. Recoil is not enough with a 44 cal round ball to whack my knuckle.