I'm 6'1" 280 lbs. My system: I smoke a couple hits sunday night,Smoke a bowl on monday nights,and take a couple hits tuesday night.I test clean on a test strip saturday morning.I drink lots of green tea and cranberry juice.
That does not mean you will test the same.Pickup some cheap test strips off fleabay. I pay about a buck a piece. And test yourself to see how your body reacts to thc.
I also keep quickfix with me at all times just in case I don't think I'm clean and I get hit with a random.