Actually, the reason more people use 2 bladed instead of 3 bladed is cost and selection. Twos are much cheaper than threes, so almost nobody is willing to buy threes to test, so hobby shops don't stock them since they'd rather stock things that are popular and sell.

Picking the perfect prop for your engine AND the plane it's going to pull around isn't simple. There are going to be a number of props that suit the power band that engine puts out. And they also have to suit the drag of the plane you have.

There aren't any rules of thumb that work. What works best is to look around (or ask around) for someone flying your plane with your engine on it who has tested some 2-blades and find out what worked for him.

Next best method is to find what props are recommended. Since your engine is an Evolution, and since the Evolution website doesn't bother to mention props.....

Most 46s spin an 11" prop decently. Most props from 5" to 7" pitch work decently. Go buy any brand of 11x6 prop and try it. If your plane is too fast, buy an 11x5 and compare both props with consecutive flights next time out. When working to choose the better diameter or the better pitch, stick with one brand. Once you've settled on dia/pitch, go buy another brand of that dia/pitch, and compare. Chances are good you won't get that far. Most don't. They realize the perfect prop isn't out there. It isn't.

After you've got some flight time, look around and you'll discover every brand of prop, engine, fuel, servo, TX, RX, tires, etc every where you look. And producing some pretty awesome flights.

BTW, the efficiency deal with 3blades is trumped up. They also have 3 blades instead of 2 producing thrust. Want thrust or efficiency? And how does any modeler measure efficiency after all. The guys flying IMAC aerobatics seem to have a majority flying 3s. And their flight performance is scored..... Most things in our hobby are nowhere close to sound bite simple.