It looks like right at 1/8" or less. I had mine made with only one "hook," and I've yet to had it even attempt to come out of my pocket. I usually wear slacks that are fairly tight, or cargo shorts that are fairly baggy, and it never comes out on either. The slacks have pretty tight pockets, and the shorts have some large pockets. When I take the gun/holster out of my pocket I normally have to grab the front of the holster with my ring/middle fingers, and make sure that my index and pinky cover the outer edges so the holster doesn't "hook" into my pocket, and get stuck. If I'm actually drawing I just grab the gun and draw - holster stays put every single time.
On mine the inside of the holster against my leg is rough, and the outer that you saw in the first pic is smooth. Purely for looks. He can make them however you like. I have a different type pocket holster by RKBA that is smooth on both, and always remins in the pocket as intended as well.
