Are either of those quotes including reflectors?
The smaller footprint of your tank (~30x12") may lend itself better to VHO or PC as these bulbs are typically mounted lengthwise and sold with reflectors that will take better advantage of a smaller tank.
The studies done with MH bulbs and reflectors refer to a spread of approx. 2' by 2' and reflect their suitability for use on larger tanks.
It's not a rule, but a guideline. The front-to-back spread from most MH will be more than you can use with your tank, IMO.
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Alan
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