Based on my research, I'm beginning to think that full suspension might just be the best method (unless you are one of the lucky few with a bottle of N lying around). I'm saying this in terms of 1. short time to unconsciousness (sets in immediately or seconds after), 2. short time to death (around ten minutes or so), 3. sureness of death (assume you perform the full suspension, there is no backing out once both feet are in the air, and death is guaranteed unless there is mechanical failure e.g. your rope breaks), and 4. accessibility.
In the book Complete Manual of Suicide, the author tells readers to look no further than full suspension, calling it the gold standard and even likens it to an art form in terms of its ability to deliver a rapid, tolerable, and effective death.
There's been many discussions regarding full vs. partial suspension, and it seems many people are interested in partial. Visually, the full suspension gives a perception of being hardcore/painful, and people seem to see partial suspension is a gentler form. However, I cannot think of any advantage that partial has over full (other than the fact that it's possibly easier to back out of). For full suspension, due to the effect of gravity + full body weight, it works by completely shutting the flow of blood into the brain, instantly depriving the brain of oxygen and leading to rapid unconsciousness. It is also possible to achieve this with partial, however there are a few disadvantages:
1. One must overcome survival instinct (with full suspension you are on autopilot)
2. There are two arteries relevant to hanging - the carotid arteries and vertebral arteries. Carotid arteries are more accessible while vertebral arteries are in a more difficult position, protected by bone structure and unable to be felt physically. In order to perform hanging most effectively, both arteries must be suppressed. In a full suspension, the gravity of full body weight and the resulting posture when hung in a fully upright manner ensures both carotid and vertebral arteries are fully engaged. With partial suspension it's trickier to fully engage the vertebral artery.
3. If not done properly, partial can lead to retention of consciousness while experiencing the distress of hanging/suffocation.
4. Sometimes we may see the head of a person turn purple while hanging - this is the result of blood being able to still flow into the brain, but with no way to flow out. It is likely that the carotid arteries have been suppressed while the vertebral arteries are still supplying blood to the brain. Under full suspension this will not be the case - watch the videos of full suspensions and you will hardly notice any discoloration. The one time I saw the head turn purple is with partial.
Watching videos of full suspension, once both feet is up in the air, there is no struggle. Consciousness is lost immediately or in a matter of few seconds. In the next few minutes, the body goes through convulsion all while being unconscious. All movement is gone typically after 3-5 minutes. Body can be declared medically dead at 10 minutes.
I don't profess to be an expert of any sort here. Please point out if I mentioned anything factually wrong. I welcome any push backs or counter-arguments. At the end of the day we all just want to learn from each other to find the best method!