For distance, I find that grip isn't that huge of a thing. I've hit roughly the same distance with all the various power grips and even fan grips. I just get a nice grip, without it being way to hard or too soft that is comfortable. Manipulating your grip for a "little" more distance is good for those trying to get 510' over 505'. Not something everyone is going to screw around with.
If you are looking to go from 250' to 400' difference in driving power... grip ain't going to get you there. Body form and release. It's about coiling up your core power right, and unwinding it to impart as much centrifugal force into the smoothest released disc you can do.
If you watch slow pitch softball swing mechanics, it will help understand this as well. In slow pitch softball, the majority of the power generated to impart distance on the ball is done by the batter. Since the ball isn't moving very fast, it doesn't have much energy to rebound off the bat. Since a softball batter has limited lateral movement in the batters box, although there is some allowed walk up, the majority of force generated during a swing is from coiling the body and unwinding it. Same thing with disc golf. The more you can get your body to turn, the more energy you'll impart on a disc when it is released. The problem is, we can't all be doing 360 spins in place. It will ruin accuracy as well as probably make you faint from screwing up the inner ear. So both softball, baseball, and disc golf use a similar mechanic in turn the body backwards around a pivot leg and reach back with the arms. Then an uncoiling happens with the lower body first, as there is more mass involved. The spine splits into two segments where the leading leg steps forward and starts the spinning motion of the body in that direction. To prevent loss of energy during the spin the idea is to keep the body as compact as possible and to have the piece you want with the most energy the last piece to spin outwards. With baseball/softball that would be the bat head. With disc golf it is the disc in your hand. You do this by placing that part the farthest back away from your body. Then when bringing it into the spin, do so at the most compact place possible which is the center of your core.
Learning how to properly twist your body into alignment for the reach back of the disc, then how to properly uncoil your body from the bottom up starting with your step in leading leg, and then bringing your arm as close to your body through the spin to have it fly out at the end is what is going to get you the most distance gains in learning how to throw properly.
Some people argue a bit on exact release angle, the exact area you should pull through, and a few other nuances like the grip. Those are what I call fine tuning adjustments. Getting down the basic mechanic is going to get the most distance out of your throw.