You'll probably need atleast 60mg succesfully vaporized to break through...20 ain't gonna do much, 40 will give you some nice fractal visuals. I gave my gf who trips face off weed 80 and she did fine, don't be scurred. Jus pack a little bit of weed, the dmt on top of that, then a little more weed. The idea is to vape the dmt not burn it, so get the bowl cherry then take the flame away. Even if the world starts to melt, force yourself to take a second and third hit, or whatever it takes you to clear it.