Hi Crank:
Prop choice sounds ok to me. However, find out what the max torque RPM is and what the max HP RPM is, select the prop that will give yoiu a good combination of the two curves. These curves may be obtainable from the manufacturer. I would not go to the 10 pitch as I believe that may be to much of a load for the engine.
If you want to slow down, increase pitch by 1/2" with same diameter, but remember you'll have to richen the needle somewhat for the engine to carry the extra load.
You need to get a reliable tach and start tuning from there. Try and fly with different prop combinations and see which gives you the best result. Then that wil be the right selection.

Crank, I will not be able to go the Miami contest, as my plane is not finished, almost but not quite. I still have to paint and set the tuned pipe header length for the engine.
Crashlander