AFAIK, all Ergon grips in the GP series have the same shape. I use the GP2s on my Nomad, as I found the GP5s to be too much bar end, especially when packing for touring (I turn my bars, but don't remove them, so the big stag horns get in the way). They're currently mounted on a GT Avalanche MT bike, but not appropriate for that use, either.
I also don't really GRIP the Ergons as much as rest on them. IMO, hand comfort is all about reducing the lateral and vertical angles in your wrist, as it's that which restricts blood flow and produces the pins and needles. I have addressed the lateral angle by using similar bars to Thorn's Comfort Bars, and they work well for me. For vertical angle adjustment, it is important to get the palm rest on the grip close to parallel with your lower arm, so that your wrist isn't bent up but rather runs comfortably straight from your shoulder to your hand. Also, you don't need a death grip, but really try and relax the hands. I learned that from years of very long days on motorcycles.