2 blade or 3 blade propeller
I looked into this same switch. A local prop shop shop said to go with the same dia w/ 2" less pitch. Think about it, 150% of the thrust area of a 2 blade, reducing the pitch takes the strain off the engine at the same rpm. The big difference that was explanied to me was with a 3 blade, two blades were always thrusting in less distrubed water from the keel, with a 2 blade there is only one.