Ran a few props on a stock, pre-revlite, Norvel .061, RC today, it is not fully run in yet and might loosen up some more. It seems like your engine guru might have gotten the AP wasp close to an old bone stock Norvel...
The APC 6x3 (for glow I hope?) is shown below next to the Graupner 6x3, the APC has the lowest load of any 6x3 props I've ever owned. Here are the numbers I got on 10% nitro:
Graupner 6x3; 18200rpm
APC 6x3; 19000rpm
APC 4.7x4; 22000rpm
APC 5x3; 23500rpm
The 4.7x4 seemed nice, I'll try that one in a plane the next time.