The "Watt's up" meter will do the trick. While you're buying toys, if you don't have them already, think about a tachometer,and atemp guage.

As you measure... Change one ANDONLYONE thing at a time.

1. Test your current setup, and get your power measurements.
2. Change ONLYdiameter OR pitch, and measure again.

and so on..

Right down everything with each measurement.

Iknow, it's a pain, it's boring, and takes time.. but it'll be worth it.

The last thing you want to happen is seeing a blue puff of smoke come out of the motor while you're doing an inverted, low altitude, high speed pass down the runway.

If it were me.. I'd be doing such a pass while someone was video-taping...