I'm with John, you can't have too many props. I don't put too many on the wall, because I don't have that much wall space. But I have maybe 5 or 6 hundred props (maybe more) in boxes, drawers, and also a wall. Most are Rev-Up or APC.

I have to disagree about the statements that static RPM is unimportant. Nothing could be further from the truth. You need to operate the engine at the rpm where it makes it power. So find out where it is rated to make it maximum power and target a ground RPM several thousand down from that spec figure. This allows the engine to unload in flight, operate at it's peak and make horsepower. Then you find the selection of props that puts you at that ground RPM +/- a thousand by changing diameter or pitch.