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.