Getting feedback from people who used the best and most effective methods in this manual has proven difficult...

There are more modern, and updated references. Final exit international publishes a ebook surveying methods, and has a community for helping prepare for the transition. wiki

A community with more active information being updated bimonthly is Peaceful Pill (wiki)

Exit (Peaceful Pill) has a large support organization and active forums for members. They often do webinars talking about end of life planning, estate planning, insurance, etc.

Both organizations charge a small fee for the ebooks but you can easily find it on the high seas (fmhy/LibGen)

But to answer your question about winners, Nitrogen displacement, and Nembutal appear to be the most favored.

Even the reviews I've seen don't want to spoil it. Maybe that's for the best.

Which one is the best? Wikipedia did not mention a „winner“

Probably some hypoxia-related one.

Carbon monoxide poisoning is a popular method in Japan for being relatively clean, easy, and painless.