Help with grow

I don't have allot of space in my place so, I started growing as an experiment mainly to test out the waters, proving theory as you will.
The experiment consists of a single plant (a fine specimen) in a 5 foot tall box 2 meters square and receiving about 55,000 lux from CFLs at 4700K.
The strain I chose was blue dream and I planted it in soil. It is now 30" tall because I let it veg for 40 days (I didn't know about the pre-flower signs) Current methods are fine but I want to go hydroponic (ebb and flow) but I don't want the hassle of lava or the dust of pearlite.
1. Is growing in rock-wool slab good to do in an ebb and flow system?
2. If so, how many babies can I plant in a 2'x2' area? Could get away with 9?
3. If not rock-wool, what would be better?
Also, how late into flowering can I take successful cuttings? I am trying to time it so that I can take cuttings off of the plants going into bloom and using two separate flowering chambers so I harvest every 4 weeks. I hate running out of stash.
And, I started a set of clones in soil. When they root, can I carefully rinse the soil off and put it into rock-wool?

Thanks for the help.