The other advantage to a three bladed blade, is that it will start spinning a little bit sooner, taking better advantage of puffs of wind.
In practice the difference between bearing loads on two or multi blade props are minimal. I tested one of my units by letting it motor for two years, left the diode out of the circuit, so that when there was no wind, the blade still spun at a minimum of 275 rpm., there was no discernable wear. The generator I was using had good quality shielded ball bearings.
In my experience, both with wind turbines and small aircraft props, the difference between two and three blades is minimal and not worth the added complexity of the extra blade.
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