Lighting

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Hi,
I'm finalizing the design of the light rack for my tank and would appreciate help on the following questions.
Tank is 88x34x30
Lights planned:
3 LB mini (16x16x7) 250 w with Coralvue dimmable ballasts and a couple of T5 lines on the front and back:

Points I need help with:
-Hanging height (I remember it was 16-18 inch from water to bulb) should I raise them more as I'm only using 3
-T5s in between the bulbs from front to back? would ...