Why does it take you long to clean out? Genetics, body fat percentage, activity level, diet, smoking an 1/8th a day, etc. 49 days isn't that uncommon for a heavy smoker.

Save your kidneys and stop drinking so much water, you can't flush out THC by drinking massive amounts of water days before the test.

Save your money now. Don't buy the head shop drink. The range for oral fluid testing is 1-96 hours. Most are about 48 hours, that's why the drink says to stop for 48 hours. You are going to be at 4 days so you should pass without doing anything but to be safe brush your mouth well tonight and tomorrow. Cheeks, tongue, gum, everything.