RE: 25 FX, Or 25 LA
Break in is the same as any other ABN engine.
Go read Dars thread on tapered bore break in. Do a search and it will pop right up.
Search for Tapered Bore or Tapered Bore Break In
Follow those instructions and it will be fine.
3D prop? Can't help ya. I have never run a glow engine that small. Someone else will be able to tell you whats a good prop.