You're correct and I agree with what you say, but like you also said, I'm looking for a "ballpark" answer and left the prop mfgr., alt., humidity, etc. to the replier. If I stated which airplane that was going to use this in, then it would be open to even more debate due to the wide # and styles of engines available for that plane. BTW, the plane in question is a Meister Zero, 108" at about 32 to 37 lbs.
Mike in L.A.