For flowering, you should aim for 5000 lumens of warm light per square foot. In other words, you don't have much light for 3 or 4 plants. It's enough for one, two if you surround them with the CFLs, and that's probably it.

If you do everything right (which you probably won't the first crop or two), then you can hope for 1 gram per (real) watt, assuming the lights are of the appropriate spectrum. That's a big expectation though, and I certainly wouldn't count on that. What I do is aim for 0.5 grams/watt, and if I get more, I consider that a bonus. That way I'm not disappointed when I don't hit 1 gram/watt (and I never have, although I've gotten close).

You said your CFLs are 60w. I am assuming you meant 'equivalent watts'. That's not a useful measure for growing plants. Those are probably 20w bulbs or something, not 60w. Read the package carefully. 42w bulbs put out like 2000 lumens, and since you say six of your bulbs put out 5000 lumens, that'd mean they're probably 20w bulbs. Assuming that's true, that's 120 watts of lighting, so in a perfect world you'd yield around 5 ounces. That's pretty unlikely though. With that setup, you're likely to get a couple ounces, around there, plus a bit of leaf.

Flower 12 hours on, 12 hours off. Veg with constant light, 24 hours/day, or if you want them to grow more slowly, 18/6.