I've heard/read that if you have more then one, to buy the 8". Other then that I think there pretty solid buy. Good luck and report back. I would like reinforcement to buy one myself :)
I run ebb and flow as it`s very easy, plus you can put quiet a bit of plants on the table and move them around very easy. I use rock wool to start my plants, then place the rock wool in/on top of the expanded clay pellets. Last but not least, I put all this in netpots, that way, like I said...
Well I'll put it this way. You say your house is at 80 degrees, correct? At the very best you will only be able to lower the temp in your box to 80 degrees. Now that is under the understanding that the temperature around your box i.e. the closet air is also 80. I would put a thermometer inside...