So would 2-DS51's be the way to go? Would that setup give me better light coverage than say one DS160? I have a friend who uses 2-YS110's. Again would that be the way to go? How do the 110's compare to the DS51's? I have a Canon G11, 99% freshwater diving, so mirky.
There are sometimes other considerations. My old school Ike SS200 has a 1 second recycle to full flash and covers most to all of a typical WAL picture. It recycles faster when you are not using full power on the strobe. I am able to get 1/8th and 1/4th power strobing for all 4 of my camera's High Speed Continuous mode.
Following the "future systems" comments earlier, a DS161 has a much faster recycle time than DS51's, works as a primary dive light and will work with DSLR's and dedicated video cameras.