Good Job Chuck! Your reward is the knowledge that you are the winner.

Both use cross control of Ailerons and Rudder. The idea behind the "Sideslip" was to attempt to get the airplane to stay on the centerline of the runway for landing in cross winds. The idea is to get the plane slipping the same amount the cross wind is pushing the plane off the centerline. You'd turn base and crab until it you felt it was time to see how much sideslip was needed to maintain the CL of the runway. Cross wind landings done correctly took skill and was something only practice ever made me comfortable with. Forward slips were in use more with planes before flaps became common. They are still good to know and are used to loose altitude without gaining a whole bunch of speed, or to dump speed.

I think they are more difficult to use in R/C because it's more difficult to determine how much or how little is needed as we're not in the cockpit to see whats going on. Foward slips are a good way to dump altitude when your final approach ends up to high. Most useful when dead stick!!