Per Johns suggestion I'd consider using a dual plane like the Performer RPM instead of the single plane manifold. Assuming you have compression around 9.0:1 it should all work ok and be very drivable.

The "A" impeller behaves similar to a 2000-2200 RPM converter tied to a 3.0:1 rear end. Even though the boat is light weight you need good low to mid RPM performance to get the hull up on top.

By the time you get to 5000 RPM that impeller cut is requiring 415 HP to turn, By 5200 you need 450 HP and the log curve is rising quick. I don't think you'll ever see the benefits of a single plane manifold.

Cheers, Mark