I'm interested in rules of thumb or examples of how big a ballroom dance floor should be as a function of the number of couples dancing (e.g., square feet per couple). I guess it would be more for smooth dances than for latin.

Thanks,
Bill

Too many variables involved for any kind of definitive thinking on floor area per couple.
Most social ballroom dance floors that I've seen resemble the top of an ant hill - very
crowded with very few couples doing the same thing. Structured dances like foxtrot are almost impossible to perform. A crowded floor
with schooled dancers can be quite different
though. If its a progressive dance and everyone moves with the rhythm, its possible
to get around quite well. I use a socialized version of international foxtrot using the most abbreviated figures and a lot of step in place movements.