In reality a flight at 60 knots with a 20 knot tailwind is likely to be most uncomefortable and not something I would want to do anyway, unless of course you are very high where the wind is likely to be smoother.
But then you have other variables entered into the equation,engine leaning at height gives a better range in theory, and wind speed usually increases with height, so you would pick up more tailwind the higher you go,but burn fuel getting higher thereby decreasing the range.
So the information gained from this little excersize is about as much use to the average pilot as knowing the average inside leg measurement of a camel!
