the 115 pounds is on your side. I weigh about 50 pounds more than you, and it took me a long time to clean up.... I would think that I had 50 pounds more of THC build-up! The young skinny stoners are cleaning up much faster than us older heavier potheads. The 2nd hand smoke will NOT affect your test. Hopefully he isn't teasing you and saying, hahaha I'm smoking and you can't! Drinking liquid prior to test day does nothing to help, but its healthy, so go ahead. Do not exercise much in the few days before your test.

Test your first morning urine. If you pass that one - you are looking good and don't have to dilute much for your test. If you don't pass that one, then test again after a little dilution. (I failed the test on my first void, but was able to pass after a couple of cups of coffee). I guess the first void test will tell you whether or not you will need to dilute. If you need to dilute, load up on creatine at least 48 hours before your test. It takes time to manufacture into creatinine. The B+ vitamin is for color. When you dilute, the color of your pee can be clear, which is a clear sign of dilution. By taking B2 or a BComplex vitamin about 2-3 hours before your test turns your urine a vitamin yellow.

So... take your tests. You'll know what you have to do. Best of luck to you!