I think Kelsey hit my numbers pretty good. I may or may not have the "optimum" but I know I am faster both sailing and under power. Also a 3 blade. It drives the boat through the water better. I used to see the stern drop down like a power boat does when powering up before planning. There would be 3 inches of water above the exhaust. No more. And I am reaching calculated hull speed. Makes me happy when having to use the engine.
I have noticed less prop walk. Backs straight, I used to get some prop walk to help me turn. Now almost none.