Lee: I have none of them myself, but I have set a few fountains up with them. Based on the amount of fog they put out, I think the 1-disc model is sufficient unless you have a very large enclosure or want the look of filling your entire chamber with thick white fog. I imagine that five of these running at the same time would look like a chemistry experiment gone wrong. I would buy the smaller models and just stock up on replacement discs.
CJ: That's a really nice build in that video! I was terrified when they filled it with gas though - in the living room, with no blast shield or anything. Pretty ballsy if you ask me... o.O