If I were you (and you were not planning to cbt with a friend or loved one), I would take both for the reasons intr0verse said. The more you take, the faster it will do what you want (and I'd also wash it down with a shot or 2 of your favorite booze, like whiskey, vodka, scotch, or whatever) and situate yourself where you will not be found for a while (12 to 24 hours would be best, even if you pass on in just a couple of hours) because you don't want to fail by waking up in a hospital because someone happen to discover you out like a light and barely breathing, but enough to bring you back from the brink, as happened to me 3 years ago, as described in my first post here on SS.