As you likely know your buoyany while doing this normally upside down and tethered into a roap band on the boat if possible. I have always played with the ides of a two stage cleaning with the 108 or something like it being the last stage or the second of two people working the hull. Have not sttempted this but why not a pressure washer with a short handle [ at ] 3500psi using water pumped from the other side of the boat. This should remove the light stuff and cut the time down by identifying the heavy stuff saved for the 108 or what ever you choose.
Just a thought