Too many variables. I'll tell you what I have and did to help in your conclusion. I have one boat with 37 gears and a 3 blade, the other has a 2 blade with 18 gears. I swapped them with no other changes and the one boat slowed down entirely on et and mph while the other dropped mph and kept the et. No benefit. The big 2 blade was on low gears with less hp, the 3 blade with bigger gears and more hp. You would think the higher hp boat would turn the prop of the lower hp boat to a better et and mph. Didn't work that way. I'll never claim to be a racing expert no matter how long I do it, but this is a fact-----IT'S ALL IN THE COMBONATION!---- When you say 2 or 3 blade, are you talking cleaver props? round ear? props can be tuned for a range of prop speeds and functions. theres alot to it. Just try em all if you can.