One plane I occasionally rent is a 172K that has been retrofitted with a 180-hp engine and a constant-speed prop. I guess because it's a retrofit the plane's POH doesn't cover operation of the prop control. I know enough to use full RPM for takeoff and landing, and to use a coarser pitch for cruise, but I'm not really sure how to know the optimum manifold pressure and RPM settings for any given mode of flight. The FAA's Airplane Flying Handbook doesn't have a lot to say about this, other than to increase RPM before increasing MP, and decrease MP before decreasing RPM. Another pilot who flies it told me "Use 24 inches and 2400 RPM for en route climb." Beyond that, and keeping the needles in the green arcs, what else should I know to use this system properly?