waterloading...not sure if you will have enough time for this technique, but ill spell it out anways for ya
your bodies tendency to hold water is based off a hormone that controls water retention...to shed excess water you need to deplete your body of this hormone
this is accomplished by water loading...the more water you take in, the more you can get it
EG...when prepping for my show I waterloaded 1 week out from the show...6 days out-1.5gal/day, 5days out-2gal/day, 4days out-2.5gallons/day, 3days out-3gal/day, 2days out-4gal/day, 1 day out-STOP WATER INTAKE, day of show-shredded
in laymens terms your body is like 'WTF IS WITH ALL THIS WATER--GET RID OF IT NOW!!!!'...in doing so your body will adjust its water-retention hormone production down to zero...by stopping water intake all at once, your body will 'overshoot' itself and piss out everything leaving you nice n dry
hope it helps...srry if its too late
