I typically cruise anywhere from 8500-11500 on my IO-360-M1B with a 74" Hartzell CS. I am curious what RPM others have found to be the smoothest. It would seem that mine really likes 2450 and above. I can certainly go lower than that but the feet buzz increases significantly. Around 2300 RPM and the feet buzz is annoying enough that I don't want to stay there for an entire flight. Anyone else find similar? What RPM do you like? Any tricks you found to reduce the feet buzz?