Thats a neet little rig right there. But I believe I would want the sides just a little higher. That is if my idea of how it works is right and that is the bottom, as it is shown, is acutally the top and is open.
I usually put a .22 between and just above the eyes or right behind the ear and towards the eye on the other side. But when I do take one out alive, I drop a noose around his neck and pull the rope through the wire near the door. Pull his head up to the wire and reach in and get him by a back leg, pull him out, throw him on his side and tie him up. If its a big un, I get some help and do basically the same thing.