Safer stooge ideas?

Yesterday I got set up behind the house for my Ringmaster's maiden flight and after one successful flight, I had a sobering incident. Having never done this type of launch before nor even seen one, I have to guess at everything. My release is 2 1/8" eyelets 1" apart with a 3" pin. After making sure the pin was in place, I cranked the engine for my first flight. In hindsight, I now see my first mistake. My wire stay that attaches the tail to the stooge was mounted too low on the plane (in the plywood tail skid) allowing the tail to lift off the board when the plane is pulling against the release. That launch went smoothly. The second did not. After getting reset, I started the engine and this time the tail began to hop up and down pretty hard because of the unrestrained elevator in the propwash. I immediately tried to steady the plane so I could pinch the fuel line but before I could put my hand on the fuse, the stooge (apparently) vibrated loose allowing the plane to accelerate into my right knee.
I got a hole in my jeans, a broken prop and spinner, and 3 minor but painful scrapes on the side of my knee.

First, I'm going to re build the wire stay so that the pull of the plane holds the tail against the board, or that, one it's pinned, doesn't have room to move.

Second, I'd like to come up with a better pin release. Something less vulnerable to vibration.

Im open to suggestions..