rule of thumb is 500 ml (just under a pint ) of water per hour of intense dancing, less if you arnt very big.

If you arnt doing anything that tires you out an make you sweat like dancing (which you will almost certainly want to do when its taken effect) then you don't need to worry bout it as much. just have 1(500ml) bottle throughout the evening.

I reccomend Gum or something to chew on so you don't chew up the insides of your mouth.

Better still, get an isotonic drink with added zinc and magnesium, they'll help prevent jaw clenching and cheek chewing.