Fender wasn't being as flippant as you may think.
72 hours is more a bare minimum than an average cleansing time.
So there is a very good chance of failing the test, even with the "studying" you've done thus far.
Many variables , too many in fact to give you a definite pass/fail answer.
short and skinny marathon runner/tall and fat W.O.W. god...(couch potato)
pure white hits/(never actually inhaled)
wall mart piss in a cup test/gas spectrometer
doctor/civil service employee/someone who really could care less.
Welcome to YaHooka.
Hope you pass.