Use the compressor to get the cylinder at bottom dead center. Be careful, it will move all other cylinders too, so any rags you have in spark plug holes might get blown out.

I used a 10 inch piece of 1/2 inch (or 1/4 inch, not sure of the size) to help guide the rope down into the spark plug hole. I also lifted the pvc tube up about 1/2 inch and used my air compressor to shoot air down the tube to help "shoot" the rope into the cylinder cavity.

After the rope goes in, use a wrench on the crank and turn (I think I went clockwise) until the rope is mashed up into the underside of the valves.

It worked great, and I'm glad I didn't try compressed air. After losing a keeper, I had to let the rope sit in the engine for a week while I was traveling for work, and waiting for new keepers to show up.