A lot more work then blowing up your balls, but.
I take the time to cut up old found dock flotation. A thin diamond plate piece for the top. Then another piece for the area between the bottom of the jack plate and the skid plate. Then fill the entire area with cut to fit foam pieces.
What I found with just the balls was the boat at rest, me standing in back looking, was riding at least 3" higher. When I came off plane there was minimum back wash if any on the rear deck. Squat during blast off much less.
Another plus is, consider the weight of the water that is trapped as you accelerate. Yes it isn't there once drained out but it has to be moved forward as the boat accelerates from off plane. "Pints a pound the world around", times 4, times probably at least 3
If the jack plate is open top and bottom when you come off plane it acts as a scoop.
I cannot think of a negative to having the area filled. IMHO