David, the screws don't matter any more since I was describing my experience from at least 27 years ago!
The important thing, compared to the OP, is that this one has *positive retention*. Mine is similar, with a spring-loaded pin that captures the hook. The airplane is completely captured and something has to break before it is released prematurely. If you feel you must fly with a stooge (and I know that a lot of people do, and are going to continue doing it), I think you *must* at least have this level of safety. Sleepy's stooge, with all due respect, is *absurdly dangerous*.
Other tips:
Run you lines *before* you start the engine. Once the engine starts, stay clear of the lines in all circumstances, do not touch them or grab for them if the airplane releases early. The worst accident I know of involved someone running out the lines when the airplane released early, and it cut his fingers to ribbons, basically "degloving" two of his fingers. That's the accident that stopped me from doing it any more. It's much better to let the airplane take off and crash than it is to amputate you fingers or strip all the squishy parts from the bones.
Before you start the engine, or even choke it, pull-test the airplane to make sure the stooge is really hooked up, and check visually that the release pin is fully seated. I painted part of my pin fluorescent yellow where it is normally covered when the pin is fully seated. If you can see the yellow the pin is not seated all the way.
Also check the tailwheel strut (or whatever else you attach the stooge with) attachment before and after every flying session. I think they have to be heavily built up for long-term stooge use. That's another reason I don't like it, it means I need to add an extra 3/4 ounce to the tailwheel mount. But whatever you use, its right on the bottom where all the oil ends up and it tends to get very oil-soaked.
Set the lines out straight, and then the stooge line about 3 feet behind them. Be very careful to check the clips so they are not flipped around and are straight. When the engine starts, walk out to the airplane *behind* the lines and stooge line. That way, if the airplane releases, you will not be in the way and get wrapped up in them, and get cable-sawed. Remember that you are by yourself, pretty much by definition, so if you get any more than a minor injury you are immediately in big trouble and a significant cut could result in you bleeding out before you can get help.
Don't choke the engine, apply the battery, idly flip the engine, without positive control over the airplane, meaning hold on tight with your arm clear of the prop. Modern engines start without the battery *all the time*, very easily, sometimes even when rocking back against compression from the weight of the piston. If the stooge isn't completely captured, and it starts, and you have no control over the airplane, it will chop you to ribbons. A piped 61 with a carbon prop isn't going to stop when it hits your knee or cuts your femoral artery or other important items in that general area. Note that it is also very difficult to control the prop when you attach the battery, and you pretty much have to reach through the prop disc to attach it, if you are holding the airplane by yourself. They also start sometimes right when you attach the battery, there goes all the veins and probably arteries in your right arm. You bleed out and die.
When you get to the handle, attach the thong, and then pick up the stooge line handle. Pull it to release the plane, and then throw it, hard, out behind the lines (off to the right if you are flying CCW). Its easy to get you feet wrapped up in it if it's anywhere near you. We have *all* done that, whether we admit it or not. Worst-case is that you fall and crash, so its not life-threatening like most stooge problems, but you will lose the airplane.
If you pull, and the airplane doesn't take off, you are stuck, do not put the handle down and go check on it. It may shake itself loose and then off it goes. Just let it run out the tank. I use the Kevlar lines for the stooge release, this has little "give" so it's more likely to ensure you pull it all the way. Fishing line, string, etc, stretches and you are never quite sure that you pulled it hard enough.
Try to land so that the roll of the airplane puts it right back near the stooge. On pavement this is pretty easy, and you can get it within a few feet with a little practice. The reason is that you are going to have to drag the lines when you put the airplane back to the stooge. Dragging the lines, they will get caught on various things on the field. When it happens, don't just yank on them, go clear the snag. Check the lines carefully after each flight for line damage caused by dragging them.
Always have a cell phone with you, in your pocket, with speed dial to 911. Don't leave it in the tool box, because you might not be able to get to the tool box. That way you can call for help if you get hurt.
The single biggest danger is getting cut and bleeding out before you can get help. Its potentially fatal, it's no joke.
To me, after seeing numerous variations on the above (none fatal, in many cases due only to dumb luck), I pretty much stopped doing it. To me, it's not worth it to get in a few more flights, and with current airplanes and engines the injuries are potentially far more severe, and 5 extra flights not that critical. I think this makes the risk/reward far different from the good old days, where you really needed a lot of flights, and we were running Foxes or ST46s with wood props. I did on the order of 5000 flights with stooges, back in the good old days, and I am still alive, but to me anymore it is just too risky.
Brett