Two things to remember on this. First, wave height is a function of water depth. Waves get higher the shallower the water is. Next, the minimum water plane area, the intersection of the water's surface plane and the floating object, will result in least vertical acceleration as the wave passes. Thus, a flying saucer form will be worse, a spar buoy would be best. Two domes, top and bottom, would not be in the middle.
Offered by Jack.