I have taught a lot of people to shoot, mostly women and kids, and the first thing I tell them is that if their hand doesn't like the feel of a gun, they will not shoot it well. Hence, when I taught a newby, I laid out all the handguns I had available, and let them pick one to learn with. When the hands were happy, the shooter usually did well, some VERY well. It can be very humbling when the novice is shooting better than the teacher! :oops:
One of the great things about the GP-100 (I've had two) is the selection of grips is nearly limitless, since there is no grip "Frame" the stocks have to conform to. A long stud can handle any grip configuration, from skinny little round-butt Pachmayr "Compac" grips to the full-sized target stocks. Let your hand make the decision. Then all you have to do is shoot it!
Be safe first, have fun second.
Papajohn