ORIGINAL: The Raven
My theorizing is that a single cylinder engine will never have a perfect balance. Adding a prop gives another plane of imbalance to the engine. It's better to have all those imbalances line up on a common plane or...theoretically...you now have two imbalances which could lead to vibration/harmonics that detract from engine performance.
Sorry mate, you've lost me. Statically and dymamically a balanced prop is a balanced prop and can be considered a disc as far as the dynamic forces go. There is no resulting "imbalance" in any plane in a balanced prop that can be used to offset the reciprocating imbalances in the engine. You need to look elsewhere for the reason for your 300 rpm increase.
michael.