Hi all, I need opinions on growing 2 big plants in 2 big pots under the lights i have

I Want to grow 2 faily large plants in there own pots, im starting from seed and not sure if i should use the clay rocks that i have or the rockwool or a combination of the 2 for the medium but the rockwool hold alot of water\nute solution and the rocks drain better and im not sure what feeding technic to use....with rockwool i normally feed it 2-3 times a day but worry about wether the rockwool meduim is still moist in the pot between feeds and the rocks i usually put it on a constant flow until the lights go off.
The next thing is my lights, A 1000w hps, 400w hps, 18w twin glow lux fluro about 2 foot long use for clones. The room is 6 by 4 by 7 foot high with 2 10inch double bladed fans. So should i use my 1000w straight up and all the way or should i start on something smaller since ass soon the seeds sprout i want to put them under the light straight away or is the 1000w too much for that even with a good distance between the light and seedlings?

Any Ideas would be much appreciated, Thanks

might look into doing dwc with the meduims you already have its probably a good choice.
its just 2 plants so you may be able to start them under the flouros and then move them under the 400 until they are ready to flower then would use both your 1000 and the 400 to get the most yield out of the 2 plants.