There are a number of reasons why you get too much radiation in the boat from tower speakers.
Volume. The louder you play to the rider at a distance the more radiation you will have near field in the boat. Its that simple and its unavoidable. Dispersion patterns increasingly narrow with distance but there is a lot of radiation surrounding any speaker when very close to it.
Lower towers, lower mounting positions on the tower and forward leaning towers create more off-axis radiation to the occupants in the rear of the cockpit. You are fortunate if you have a taller tower and a rear leaning tower.
If you have stacked and staggered speakers like on an Illusion then the upper forward speaker will reflect off the pod of the lower and rear most speaker and spray the cockpit with more energy.
But many overlook that tower speaker volume is not the only thing that alienates in boat occupants. Standard car stereo speakers can't make the distance without being driven into distortion. Smaller HLCDs are peaky and brutally bright. Larger speakers are generally warmer, smoother and better balanced. Over-driving the tower amplifier or tower speakers creates a lot of harsh distortion that many are more sensitive to than the high volume.
So having fewer, larger, better, smoother, warmer, more powerful speakers plus more amplifier power so that you are running everything conservatively and clean helps.
You are on the right path with the Wetsounds REV8s. Make sure you have enough power to keep it clean.