Good luck.
He cannot find any technical data (supported by hard facts) to support his hypothesis that 2 blade is more efficient than 3 blade.
That's because there are way too many things that affect the efficiency of propellers.
He will of course have to come up with two "identical" propellers, one of 2 blades and one of 3, that produce very close to identical thrust. Or that require identical power.
Then unfortunately, how does he prove the difference in efficiency isn't the difference in propeller blade aspect ratio, a detail of wings and props that very strongly affects efficiency. If he adjusts the blades to have equal aspect ratio, they certainly won't have similar total blade area, also unfortunate since "wing loading" affects efficiency. There are way too many details that affect efficiency.
It is almost impossible to isolate the effect of tips on the efficiency of a propeller because they have so little effect compared to blade area, blade aspect ratio, blade profile, blade twist, blade stiffness, operating rpm, operating speed, etc etc. The old saw that, "2 blades are more efficient than 3" has led so many astray because there really isn't proof other than the irrefutable fact one prop has an additional tip and therefore 1.5 times the tip drag. It also would have 1.5 times the thrust. If it was turned by 1.5 times the power that is.
The reason the old saw has lasted so long is there is almost no way for modelers to make anywhere near a sensible conclusion.
Full scale aeronautical engineers have put little effort into it because it's of no real consequence. They build props to match the envelope. How many blades required to get the appropriate blade area is what they're after.