I have never heard of a drip feed DWC system, a DWC system by definition can not be a drip feed system. Building your own DWC containers is so much easier and cheaper than buying them. You can build an 8 plant DWC system with air stones, hoses and pumps for less than $25. There are many examples of how to on here. If you are new to it I would recommend doing soil first since it is much more forgiving.
There are many things you need to consider in order to best utilize your space...
for example:
Are you going to have a mother and take clones from her regularly? If so I would cut the area in half so that I had a mother chamber and a flower chamber above and below each other. If you are going to be growing from straight seed this will not be necessary but since you are growing in a limited area you want to waste as little space on males as possible.
Cut the area in two. About 4 feet off the ground install a shelf and grow out one mother in the bottom. Then use the top half for flowering. In that space you could use a 400HPS and in the mother chamber you want roughly 100 watts of CFL's. If you can remove your heat and circulate your air well you should be fine.
One other drawback with the DWC system you describe and one major drawback with most DWC systems is that if your system does not have segregated growing containers, then all of your solution in the DWC mixes. This means that you CAN NOT HAVE PLANTS IN THE SAME DWC AT DIFFERENT STAGES OF GROWTH because different stages require different nutes. This means that you would be harvesting one batch of plants every 60-70 days or so. If you can do a DWC system with each container holding only one plant or go with soil then you can stagger your harvest. This means that in a 6 square foot area that you can cram 6 plants into, you could harvest a plant roughly every 10-12 days.
