Except that any part of a gyro below the rotorhead that adds any lift, also unloads the rotors... which is extremely destabilizing and dangerous for a gyro...
All he needed to do was make the top of the floats before the CofG come up to a spine, like a triangle... so if the floats go too nose down for any reason, the airflow cant push the front of the floats down and flip the gyro forward... that is why many aircraft floats have that 'triangular' aspect on the top front of the floats.
Also, I would think that flat bottomed floats would be more likely to 'stick' to the water... that is why most floats have the slight V hull and a step somewhere around the CofG... so as they gather speed, the floats plane on the front part of the step and the rear either is very low in the water, or out of the water... allowing a plank to 'rotate' for take off?
This is a good question for Lofty