I think they recommend the 22A or 22B....however if you want a bit more load on the engine and less revs, the 23A should be ok. I would think if its your first prop on the engine, the 22A would be better. If you have burned some fuel and have the DA50 well dialed in, the 23A might be a better choice.

I have not purchased a Vess yet, but I have talked with the factory on several calls and thats what they told me asking pretty much the same questions. They actually seem to encourage the B props first, but I think if you want 3d the A is going to be a better choice.