First off there's a post on 8chan that includes some important details
https://8ch.net/suicide/res/36746.html
For those who's only possible location is in a tent I'll be writing up a post with my plan to avoid the tent melting etc etc and my reasoning for the details in my method because I know some people disagree with entering the tent at the same time as your charcoal. However I believe most ill-effects actually come from smoke and the toxic gases in smoke, if you wait until all smoking and flames have stopped, charcoal will still produce CO for hours until completely turned to ash. If there are no flames and little airflow then you know CO is being produced.
I'll be using a chimney starter like this post suggests just to be sure I have evenly burning charcoal, also be using a steel bucket and a tray of cold water to catch the downward heat. Upwards heat once the flames have stopped can be intense but it dissipates quickly. My tent is 100cm high in it's highest points so I'll probably place the bucket/tray in the centre of the tent and curl around it with some headphones in after taking some pills and drink.
I'll make another post with detailed explanation of my plan and a little diagram very soon before I go, watch out for it and if I don't respond again you'll know it was successful and the info can be archived.