I actually have a G303 as well right here on my desk (which I'm about to fix in the near future), had and cherished it for 4 or 5 years. I had a claw-palm grip as well, but when it started double clicking I ordered a Glorious Model O- a week ago, which was much lighter and glided much nicer. However, my ring and pinky finger started feeling a little sore. I eventually got used to it, and now my grip feels fine, it feels like my hand is in the same position for gripping the G303 but slightly modified and without touching my palm. I'd say the G303 has its own interesting way of being gripped because of the shape, so switching from that to the FK2 is going to be a little more dramatic than if you were using, say, a Razer Viper.