Um..
30 plants X 24 oz = 720 oz =25.7 pounds
2 pounds = 56 oz
56 oz / 30 plants = 1.86 oz/plant
2 zips a plant should be not that hard in a 5 x 6 matrix.
If I could pull close to 1/2 pound under 400w HPS 2.5'x2.5', he should be able to pull 4 x's that with 5 x's the light and 6x's the sq footage.