Which Light is better
 

You have 2 4ft fixtures

1. has 4x 24w T5 ...so they would be 2 per row

2. has 2 x 54w T5

so which is the better setup?

39w is 3 foot bulbs I think...

I agree with Brett, plus I'm pretty sure the Lastlight is the best of them all.

lol

Har har!

Yes you are right. they are 3ft...okay I corrected my mistake

If all things other than the bulbs are equal (reflectors, ballasts) then I'm sure more wattage will mean more output (option 2)

Plus it will be cheaper to swap out 2 54W bulbs over 4 24W bulbs.

I would have thought the 4 bulb setup to be better because you have 48 w centered on two places rather than 110 averaged over the entire tank

54" bulbs have better penetration and are stronger.