As I was grilling tonight, I took note to how the coals work. Once they are burned to an ash grey, they burn hot and they burn clean and they burn for a LONG time. These were charcoal briquettes with lighter fluid, which I have read not to use.
Big letters on the bag: carbon monoxide can kill you. My only concern would be heat. I had planned on using this method in my vehicle using a portable grill and a chimney starter to avoid using lighter fluid. The portable grill would be adequate for a proper amount of charcoal, which seems to be around three pounds according to this post.
However, judging by the heat it gives off, this might not be the best location during the summer months (which I am currently in), so my next choice would be my bathroom. It's the smallest room in the house if I can't wait until it's colder. I can easily seal off the bathroom fan and door gap. I figure with a larger room, I could light up my medium size grill outside and when it's done burning just drag it into the bathroom. This would yield about five or six pounds of charcoal.
Either option would give one plenty of time to prepare to drink or take sleeping pills to aid in falling asleep. By the time it burns off, and builds up the carbon monoxide in the enclosure, I feel you could be well on the way of being a bit drunk or sleepy. Both of the options would work for myself, as it would be well into the morning before I was found in my vehicle and possibly a few days in my bathroom. I have no one to check up on me.
I am avoiding reading too much into this method as I believe it is about as fool proof as you can get with proper preparation and overthinking it will lead to mistakes. I also believe this method is the best as most internet sites avoid discussing this method because there is little to go wrong, so kinda "we won't mention it because we don't want anyone knowing about it."
So to sum up, I believe with proper preparation and avoiding calculations, overthinking measurements and what could go wrong, this method is your most peaceful and solid way to "shuffle off this mortal coil."
I hope this helped anyone debating this method.