I haven't tried the Wilson, specifically, but the other drop-in beavertails I've seen are not entirely satisfactory. they have to be narrow out to the end of the frame, and when you depress the grip safety, that narrow extension comes down and wears a red place in the web between the thumb and index finger, just the same as a regular grip safety does. If your wife's hand is bothered by the standard grip safety, she won't get the same general spreading effect of a broad BT grip safety unless it is installed by removing some of the metal at the back of the frame to make it fit.
