Something else you might try. I don't how big your hands are but if you are a big guy you might consider going up one size in revolvers to the S&W K frame in three inch barrel.
Like Berto said, once you go to a really bigger grip it defeats the purpose of the J frame. You reach diminishing returns to the point that a K frame would fit. If so, you will have a better trigger and could go to 357 magnum. A K frame 357 shooting 158 grain SWC LHP P+ ammo is a serious fighting handgun. A 357 would be "more better".