At the rpms our engines operate, three blade props absorb extra horsepower without producing extra thrust. Most full size aircraft that use more than two propeller blades utilizing gear reduction units to slow down the rpm of the props, where they are more efficient.
Wrong on both counts. There is some lost efficiency, but there is extra thrust from the extra blade, but many engines will slow down too much to notice, unless the diameter or pitch is less. I know of no gear reduction specific to full sized props. I have a pilots license and except for turbo prop planes gear reduction is not used nor needed in a full sized plane. In full sized planes multi bladed props are used for two things, prop clearance when more prop area is needed, or high speed high altitude flight. The higher and faster you go the high speed smaller column thrust is what you need. A jet engine being the ideal.
In pattern three bladed props are used for two things, prop clearance when a taller gear is not possible, or just looks stupid. And to get below the strigent noise rule that pattern competition has. I would not bother with a three blade prop unless you have one of those problems.