This isn't about the pictured grip mod, but just as an idea, I personally hate the position and shape of the bulge on the left side of the stick for the side button. It's too low for my thumb so there's a huge amount of travel going from the buttons on the upper back of the stick to that side button (on my combatstick that single button is my machine-gun-only button), and the shape of the bulge annoys me because it blocks the natural curving-around of my middle finger around the grip. Combine moving that side-button bulge up a half inch with maybe a 1/4" chop like that pictured (except 1/4" instead of 5/8") I think it would greatly improve the ergonomics of that stick.
