Here's my favorite J-Frame Centennial grip:
It covers the entire backstrap with rubber, has a tamer insert, and adds enough length for a pinky. (Extends 0.41" below the frame.) Made by Hogue, these run about $17 from MidwayUSA. They also have a plastic buttcap that prevents cloth sticking and holds the grip on to the frame. It's an ingenious design that is lightweight and has no metal in it.
The target was 10 rounds at 7 yards with 135 +P Gold Dot. This is my carry gun with my carry grips and carry load.