I've broken in an OS 15FP for use in a Clancy Lazy Bee and here are some numbers:

14,400 max and 2800 good idle turning a Master Airscrew 8x4 and burning Morgan 10%. Run in for two 8-oz tanks.

Seems reasonable to me, although I might tweak the idel down to 2500, and try a "more thrust, less speed" prop like a 7x5 or 6.