Why do have to take the UA in the first place.. If its for job were you not monitored the whizanator is your best bet.. You could use condom with some elses urine..
If you 6'3 230lbs i doubt your gonna be able to flush in time...Im not a doctor or anything but ive quite a bit of experience with this subject..
My roomate failed her UA because me and her husband(another roomate) smoke on the daily.. She doesnt smoke at all not ever she hates the way it makes her feel.. Shes got a lil extra around the waste and she tried a 2 week flush with niacin and lots of water.. She also worked a lil here an there... The point is she failed just from second hand smoke...
Fake pee is the way to go man,, unless you only smoked a bowl or something i wouldnt risk it...