Like everything else it seems like, engine height is a compromise. Raising it so high that the AV plate is above the water line may work magic on your top end, but if you can't get a skier up, or pull a tube without venting the prop, that top end speed may be worthless.
My advice would be to try it - but make sure you use it for a bit to make sure you don't run into anything like above. A simple prop change can make a difference here as well. One prop may work fine with the engine mounted high, the next not so much....