I think that you will be ok. IIRC if used properly some of them can cover smoking all the way up to the drop...just make sure that you fallow the directions to a T. With the one that this little head shop locally sells you drink it then fill it up with water drink that NO MORE NO LESS. Piss 3 times drop piss on the 4th no later then the 5th...
@least that is what I remember when the lady was talking about it.
Hope this helps and GOOD LUCK!