Sam, Pm sent.
Props are a black magic art form. Prices start around 50 for an aluminum cheap prop. They go up from there. We have a 14 1/2" diameter x 33" pitch lab finish Bravo 1 4 blade that was fine tuned by Dennis Cavagnaugh (read GOD) that I could get 1500 cash tonight for. I have seen 2 identical boats, same power, same fuel load, driver, engines, drives, oil, etc that handle and run completley different with the same prop.
Most boats wont see any benefit with a 4 blade until it is over 4k lbs, or running over 70mph. I have seen 75 mph boats with 3 blades that handle almost dangerously change to no hands driving at 80 mph with a 4 blade, there is no set standard, nothing to read to learn about it, go out and try it type deal. A lot of people have it in their heads that a 3 blade is easier to turn, and will be faster. In theory it is, but you also need to remember that a propellor is not 100% efficcient, I have seen 3 blades running at 18% slip, where as we have gotten 4 blade boats down to 3.5% slip!
Even sterndive boats have impellors that will get damaged by sicking up crap, but these small rubber impellors are used to push (or suck, depending on the drive) cooling water into the engine.