thats an odd shape..
I would go with 8 individual reflected and run 2 Ice Cap 660 4bulbs each..to overdrive the bulbs to give you the penetration you need on that deep of a tank.
then get some good bulbs
like
ATI blue+
ATI Aquablue special
UVL Aquasun 10k
Giesemann aquablue plus
you should be...