From my understanding, the notches are 22 x 22mm. If you need to add length to your kidney, using the molded in cut out location, i.e. AP kidney, they would be much longer than 22mm. By going what you're saying and having the notch start where but butt plate meets would mean the notch needs to be longer than 22mm. I see from Pandatroopers thread asking about this, it is in the air until after elections.