What is the problem? The 22/8 is a common prop for this engine. Zinger are kind of a sport prop IMO. If you looking for more pull a Menz S, Bambula, AirWild, 3W and many others are well known for loading the engine a little harder and providing more OOMMph.

Increasing pitch loads the motor harder and may provide additional speed and better down line braking. Stay with the 22" prop for best results, a 23/24" would be even better if the Zenoah could pull it. It depends on what your looking for. Prop diameter only effects the static thrust delivered and is a variable of RPM... Pitch is a speed thing for the most part...

Composite props are heavy, much heavier. They typically have a narrower chord and are easier to turn. If you want to go hear try a Mejzlik 22/8.