ORIGINAL: dick Hanson

the lower pitch prop is less load on ths engine - so heat build up in cylinders will be less - that is likely why Mike recommended it
-If you set mixture correctly and use throttle carefully (as you mention) - use any prop you like which will make good performance for you and not overspeed or over tax the engine -
the relative prop drag on that model is pretty small.
I would suspect you don't do much full bore flying --