Hey shadetreeme, I think that, while these are excellent lights for many tanks, your tank is a bit outside of what these lights are designed to be used for. They certainly don't make a six foot model. Perhaps 4 three foot Ray 2s would work but they aren't designed to be mounted partway over a tank, and in the center where the light fixtures would meet, your tank would have a dark area. I recommend T5s or some other LED system.
I do use a Finnex Ray, and I plan on getting another one for my next build. I'm very impressed with it.