I had a chance to fly my 58 (stock BIG muffler) with a Vess 23a, I only flew a few minutes because my plane kept disappearing. The conditions were less than ideal, 40* and fog. I could pull out my old E6B and tell how far off standard conditions that is, but it might not have had that great of an impact on my numbers. Although, when I landed my plane was washed for me, it was dripping wet.

In stock configuration you should hit about 7300 +/- on the vess 23a, and have about 28-29lbs of static thrust. I was too lazy to re-adjust my needles, did not want to lay on the wet grass.

I seem to have to use tad more throttle to fly at similar speeds to the menz-s 23x8 (I was hoping for that) and pull out of hover seemed a little better on the hole shot, but did not steadily increase speed vertically as much as the menz. Then again, I could not go vertical very far before I lost the plane.
I can't wait to try a tuned pipe and hit 7900 on that vess or menz, both very good props for the 58, That would truely be better than foamie power