Volume of plants in small grows

[llama farmer]

Stolen from somewhere else on the internet and purely for example purposes is this square container bubbler

 

http://img263.imageshack.us/img263/276/bubbler022cb8.jpg

 

 

For small scale grows is it worth loading a system such as that up with 3/4 plants?

 

I'm looking at having a go at a small stealth cabinet; Very small fluro mother/clone room on the top/bottom and a main chamber 150/250/400 cool tube with a couple of plants in a drip/bubbler system.

 

So what is the most effective for a general yield be it scrog, tieing down, toping, natural or whatever for these stealth setups? 1,2,3,4 plants? Less plants more room to grow? As many as you can fit regardless of them getting in each others way?