I would try a few sub-breakthrough doses first. Not too many, but at least one or two to let yourself know that your spice is ok to vape, and to let yourself get ready for the real thing... In the end there's not much preparation you can make I think. You should always ever only smoke an amount you are comfortable with; at least in the beginning.
dmt is such a wonderful tool to work with and has so much to offer, it would be a shame to have it scare you away from the start because you were trying to get there too fast. Even if it doesn't scare you it might make you feel like you are going crazy because of the strange things you are experiencing, if you don't get a feel for the strangeness prior to some major break-through. So take care, try to feel inside yourself what you are ready for. With proper vaping technique 30-40 mg are a break-through dose in the GVG, sometimes even less will work. I would start with lower amounts if I were you.
cheers & love
Enoon
Buon viso a cattivo gioco!
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The Open Hyperspace Traveler Handbook - A handbook for the safe and responsible use of entheogens. ---
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