I asked Col about LG. Answer: Nah, brown water. No good.

He did think that the flat water might make a nice texture with the sun reflecting off it though.

I can see one problem though. It may be very difficult to line up and go on demand to take turns for the chopper to follow.
Which made me think about a launching platform. A portable structure about three steps long and half a meter wide. Carry it out to about half a meter of water. Stand on it with your board next to it. Take two running steps and step on. Away we go.
Waddaya recon Tony?