The effect you describe sounds really intriguing, so I will also un-lurk
for a moment to give my perspective on theatrical fog as a dancer (15 years
professionally; Milwaukee Ballet, Louisville Ballet, Joffrey Ballet,
Metropolitan Opera Ballet), in case it's helpful or reassuring.
My least favorite fog is the dry ice kind which hovers over the floor. If
forced to breathe it for very long (hiding under it, close to the floor)
it's easy to hyperventilate. Worse, thick dry ice fog can leave treacherous
wet spots on the floor. I have never had a real problem with the chemical
type, though; it's just unpleasant to breathe when there is lots of it. It
sounds silly, but the flavored additives seem to help a little! Obviously,
the thicker you need the fog to be to achieve the projection, the more
uncomfortable it will be for the dancers. My suspicion is that it will be
challenging, but not impossible to get used to. Visibility and oxygen
problems may require extra stage rehearsal time ($$), so maybe that is
something to consider when you are budgeting. Obviously, if you want the
opening performance to go well, you must give the performers a chance to
work with the situation.
Best of luck! And, thanks for your consideration of your performers!
Company Dance Notator
Paul Taylor Dance Company
Dance Notation Bureau