It is a question of the psyche whether one can trust a single method.
And there is Murphy's law, which makes a hedge appear sensible.
I know very well that with SN I will surely die. But I still can't be sure before I do it. That's why I'm preparing a simple and quick plan B so that I can kill myself if I wake up again. I will wear a loop around my neck and place the wooden stick for the tourniquet next to me.
I've already tried it and only survived by chance, so I know how extremely easy this method works
Here's my suggestion for everyone who can afford it.
(you do all this on top of skyscraper for maximum effect)
1) You get a tent and plan to do it in winter. You go for CO method.
2) You also drink lots of alcohol to increase heat loss.
3) You also strip naked for hypothermia.
4) Then you take SN
5) Then you take N.
6) Just to be sure you use inert gas over head.
7) In addition you make sure that you have weights tied to wrisst and hanging over edge of skyscraper, to the point where you have to use muscles to stop from falling over - once you go night night, over you go to your doom - in case you're not dead already.
8) When you pass out the weights pull you over edge and onto a train track, so that even if 1-7 above haven't killed you, there's still a chance.
9) In case you miss there is a sea or river under train tracks so you can drown, OR you place portable swimming pool under where you might land.
10) If you can also rig up a shotgun blast to head as well, on the way down, then this is the perfect suicide method.
If you survive all of this then you are Connor McCleod of the clan McCleod and you are immortal.
So ya boo sucks to you.