ogriv,
I Got Hit has pretty much summed it up for you......I've never owned that engine either, but here's what I usually do to determine the best prop/engine/plane combo. As I Got Hit stated, first, think about what you want from the prop engine combo and then buy a few different props.....test fly the plane with all of the props, and try the same manuevers each time with the different props......then decide which to keep. The type of plane will have an effect on what the best prop to use is. (not so much in a trainer, but when you start moving to other models, it will make more of a difference.)