RE: Surface vs Submerged
Submerged prop setups. More drag on motor, smaller prop diameter to keep RPM's up, however you have more control with trimming proper ride attitude with the strut angle to the hull, which is a speed and handling advantage, less prop walking. Boat stays glued better in the corners.
Surface props. Half the prop diameter out of the water, big diameter fan-style props are used without sacrificing RPM's. More straight-away speed can be achieved, but a decrease in ability to make trim changes. More cavitation in the corners, spin-outs and more prop walk tug in the straights. Risk of hurting the motor is greater, due to freewheeling over the bumps.
Thats about all the free thoughts I have. Let's hear more......