I'll let some of the more sophisticated folks directly answer your question. Also, I have never flown a PAW, so my experience is with other brands. Basically, to fly stunt, you want the engine at the lowest compression and leanest setting which gives you a consistent fast run. If it burps in level flight it is a little undercompressed. If it burps in maneuvers it is too lean, or you have a tank problem. If it slows down in maneuvers, it is overcompressed.

I have found that as I run engines over time, the right setting progressively moves toward a hair lower compression and a hair leaner. I would say once you get a needle setting you like, leave the needle alone. Because a diesel is fuel efficient, a tiny change of the needle makes much more difference than with a glow engine. So far as tanks go, I fly only uniflow tanks.