Why do you ask?

I've tested a 12x6x3 on a 46AX. Did ok, marginally. Cut it down to 11" diameter and it did better. I wanted to run a scale looking 3 blade and wasn't looking for anything beyond "decent flight". If there had been any 5" or less pitch 3blade Master Airscrew manufactured, I would have cut and tried until it had flown decently. Then would have decided if what remained looked scale enough. But such is not manufactured.

Our glow engines have very usable power over a their decently wide power curve. I fly a 14x7x3 on my OS91FXs and they fly excellently. And the suggested 3 blades for a 90s are 11" and 12". So don't let today's expert advice slow you down. Test beyond what "everybody knows" and you'll find out that everybody doesn't. I worked out the props for the 91s to find a better scale look for my H9 warbirds. One day I had my Sukhoi flying good and hard, and remembered how well the warbirds stunted with their "too large" props. When one of the too large suckers was bolted on that Sukhoi, it freakin came alive. OK, it did better than it'd done with a 2blade that was being flown because it'd won out against a handfull of other 2bladers.

It's amazing what we discover in this hobby when we go beyond what everybody knows.