I like the 12x8 running 30% heli fuel on mine (similar to the Venus) for pattern flying. I like the 13x4w for 3d, the 13x6 is a good in-between prop (best of both worlds).

I remember reading that you should try to prop it for around 10,800 max. rpm. If I find it I will post it.

Breakin?? ditto what blvdbuzzard says (I still keep it a little on the rich side).

Tuned pipe?? Don't think 4s really need them (although I have seen them on a few planes), not sure how it would be effective. This engine on this plane should already be a missle (I fly pattern sequences at 1/3 throttle most of the time).