Check out my journal and the journals of other people with this tank. Lots of discussion on fixtures.
Finnex fixtures are great but they will provide a ton of lighting. You will have to raise the fixture extremely high above the tank and will still have to use pressurized CO2 and EI fertilizer dosing.
what is your opinion for this light: "AL-H18DS: Finnex RAY II High Output Unibody Ultra Slim LED Fixture - 18" Daylight" I plan on just using stones and carpet plants. I like the light since it spans the whole length of the tank, I am also open to other suggestions if you can help?