Being tested randomely, starting anywhere from october 10th on

OKAY. so i used to be a daily pot smoker in the summer, i love the weed, been smoking it for years. last time i smoked was september 5th, due to a current program i'm in dropping a drug test on me that i failed. However, a friend on the inside got me out of it, and i get another chance. now, i love smoking pot and am not ready to totally give it up, however i am greatly reducing the amount i smoke. These tests are monitored, at complete random, and use a urine sample. i am given a 40 day grace period before i can be tested again, because this urine test (a kit available at cvs, don't know exactly what brand) claims it can pick up marijuana if its been smoked at ANY point in the last 40 days. now i've done a lot of research, and i don't totally by that. i was wondering, if i took 1 large puff of marijuana every so often, what are the odds that i'd fail this drug say, two weeks or more after that? sorry for all the text, just had to give all the details:hippy::thumbsup:

Must be on probation?
I would buy some thc strips off ebay and see how well your body metabolizes thc. Then you maybe able to find some middle ground where you might be able to smoke a little.