His question was when to move them from flouros to a hps/mh lamp rather than how many hours to give a plant ligh.
You can put them under the MH lamp for vegging after the plants have rooted well in the cubes, but keep them about 36" away from the 1000w veg lamp, its too much light closer until the plants are around 6-7" tall.
start to finish with real light. as long as you dont physically burn them up close, the real light is what you want start to finish why waste time with cfl