I have had a few boats over the years. I have a bracketed V-20 now. The motor height is one of those trial and error deals that can cause ventilation issues if too high. The best advice I can give is have someone at the wheel while the boat is on plane while you climb to the back of the boat and see where the rushing water is with respect to the anti-cavitation plate. Right now my motor is sky high for top end. I can clearly see water rushing across the lower unit 2 inches below the cav plate. with neutral trim. Typically you want the cavplate riding at the surface of the water. Even at that height I do not have any buffeting nor is the prop loosing bite on the turns. If I stick the bow into the face of a wave it is possible to hear a little prop slippage. Mine is maxed out high IMO. I tried a 17 x14.33 a 19x13.75 a 21x 14.5 and a 23x14.25 all three blade and none of them lost bite in the turns.
I agree that a 4 blade prop has more bite than a three blade. From what I read the 4 blade props typically reduce RPM when compared with the same pitch 3 blade. Depending on your setup you may need to drop the pitch down going to the 4 blade. To avoid having two super shiny wall hangers, try one before you buy it. Ken at Prop Gods is a wealth of info on props and can facilitate just that. Ferm helped me to find him. BTW- I love the way you post, you make me smile. Glad to know I am not the only one talking to the boat.
And Shrek, that is one of the best explainations I have ever read.