12G Long XM-L L.E.D Design

[crf529]

After a long break from planted tanks due to many, many moves, I'm thinking of starting up a 12G long for myself. There are a couple of reasons I'm leaning towards an L.E.D build....

- I want the lights to be somewhat minimalist like the tank (ie. not a 2xT8 3ft light, which is nearly as big as the tank...)

- I'd like the versatility to be able to run the tank as low, medium of high light without using T5HO suspended 2 feet above the tank and the ensuing light spillage/space requirement

- The tank will house a betta at some point so any light source will need to be able to overcome the ~40% loss a fibreglass mesh top will bring

- PC lighting would be a good way to go, but a solution for me is near impossible to come by in Australia, very little choice

- The sheer cool factor and shimmer effect


With that said I'm thinking of 5x Cool White Cree XM-L's with 60 degree optics, suspended 7" above the tank (15" above the substrate), spaced at ~6.9" and driven @ 1000mA via a dimmable driver. Using Hoppy's formula that's floating around, this should give about 81 mmols at the substrate, and about 50 mmols when the 40% reduction via screen is taken into account.

At the surface of the tank there should be no light spillage:





And there should be near complete coverage at a depth of about 2":





So is there anything I'm missing? Am I on the complete wrong track or does this seem logical and workable?

Any advice or discussion would be much appreciated.