I typically do not go over 9 plants in just a 3 x 3 tray with one 600 watt hps. So in theory you can easily sustain growth to the existing number of plants with the number of lights you have. I have a friend that has about 80 plants and is just using two 600's and 1 1,000 for flowering. Too me that is too many plants for too less of a yield per plant. Also more plants means more time investment and more opportunites for uninvited guests in the form of pests and disease to run rampant with you missing them because of the numbers in a confined space.
they are 4x8 trays 24 plants per tray 3 lights per tray 8 plants per tray. is this over kill or is this not enough? they are hortilux bulbs. I don't know if it matters but im doing the flood and drain method in six inch grodan cubes.