That's 72 watts of lighting. But CFLs aren't as efficient as HPS lights, so that'd probably yield around 35 or 40 grams. An ounce, ounce and a half, two ounces if you're lucky and everything goes right. That'd be a lot of work and hassle for not much reward, so I'd add more lights. I bet you could get eight 26 watt CFLs in there, which would help your yield considerably.

If you use the fans for exhaust, which makes the most sense, put them on top, and put some PVC pipe for passive intakes at the bottom. Paint the PVC black to absorb light, especially on the inside, and make sure you have at least one 90 degree bend per intake, preferably two. You'll need to lightproof the whole box as best you can before flowering.

Good luck!