OK, I have an IceCap 430 ballast that will fire up 12' of VHO bulbs. Would I be better off running 2 @ 6'. Each bulb is 160 watts or 320 watts total. Or, run 4 bulbs @ 3'. Each bulb is 95 watts or 380 watts total. The 380 watts should be about 20% brighter, but is it? Does it make that much difference? Is the amount of light output linear like that? Cheaper to buy 2 bulbs than 4 and also dont need as many end caps. Thanks for helping out.