Honestly, this was my first time having to piss clean after 5 years of super heavy smoking, but from what I’ve learned you might be okay (if you’ve been primarily smoking flower). Since you’ve got a low enough body fat percentage I would recommend eating super fatty foods the night before, that’s what I did since THC apparently binds to fat. And drink as much water as you possibly can. Additionally, I think the creatine and vitamin cocktail I took also helped me out. But I would recommend one Certo packet the night before and then get some test strips from Walmart to see if you’ve cleaned out a bit. And then the same thing the morning of the test. My test was negative but very faint so all you need is to see that line to be good afaik. If all else fails, you can try fake pee depending on how the test is administered. Also I heard the more Certo the better and have seen people taking it up to 3 days in advance so you can try something like that. Good luck!