I played with different props on my 2520 MVSC a good bit last season, so I can give you a little insight.
When I bought my boat, it was wearing a 13 3/4x17 black painted Yamaha stainless 3-blade prop.
I did a number of on-water tests where I recorded speed and engine RPM (I don't have access to the data right now), and concluded that I had a lot of prop slip. Since a lot of people have had good luck with 4-blade props, I tested several of them.
In my case, I didn't have the bad experience that Dale did... Performance was better than the original prop that I took off, but I was still getting a lot of prop slip. The 2520 is a heavy boat, so expecting a single AL prop to give good performance without flex is probably asking too much.
The prop that I'm wearing now is a 15x17 Solas AL prop that has a more open exhaust port that the manufacturer claims yields a 5 to 10% increase in horsepower due to a less restricted exhaust. I cannot confirm an increase in power, but the exhaust tone is definately different and the hole shot is much improved.
This particular prop is the best I've used to-date, but I believe it is still a bit too much prop. Last year on flat water my boat saw 33 knots at 5100 rpm from my 1997 Yamaha 225 OX66 at WOT.
My thought is that a 15x15 stainless prop should probably put me closer to 5500 rpm at WOT which should be optimum for my motor. Trouble is, 15x15 stainless wheels aren't exactly a common size.
Like most people, I almost never run at WOT. Most of the time I run between 4000 and 4300 rpm at cruise, so whatever wheel I try this coming season has to continue to give me the same mid-range performance the 15x17 Solas is giving me now.
Tuning a boat with the perfect prop is indeed voodoo science.
Good luck in your quest!