I bought several drug tests over the counter. Each of them was the same dip strip test that was being used by the place i tested at.
I stopped smoking for two months, and tested clean. Prior to that I was smoking 1/4 per week, and my usage is pretty consistent to that.
I took 3 hits off a joint. Tested positive the next morning. I tested at the end of the week, clean.
So I smoked a whole joint, waited two weeks. Took my test, passed. Took and official once, passed.
I think the whole key along with diluting the sample if possible is to make sure you eat fatty foods and **** out as much fat as possible the day you test. THC and cannabanoids are not water soluble and will be easier to **** out than pee out. A gallon of fat will deplete more Cannabanoids from your system than a gallon of water.
FWIW my body mass index is obese and I am not exactly the fastest metabolism in the world.
So.. i know you can get away with it. Its just a matter of Binging on McDonalds, Aerobic exercise, water and time. If you lack the week or longer it takes, DONT!