If you want to do it peacefully, then I'd definitely stay away from hanging. This method can be extremely reliable, but it can also be excruciatingly painful for a few seconds or even longer.
SN may not be a particularly good combination with either hanging or jumping since both of these methods are fairly instantaneous, SN usually takes more than 30 minutes to take effect, and the symptoms are debilitating enough to make these simple methods a very complicated endeavor. Sure, you could take it just seconds before jumping or hanging, but that may be overkill at that point, and the SI from just drinking SN while also having to get the courage to jump or hang may be really hard to overcome.
I agree with SN not being as peaceful as most members think it is, but the reality is that there is a level of pain or discomfort to almost ANY kind of death and the risk for even more pain should things go wrong. And SN is still probably one of the least painful and most reliable methods that we have, far more desirable than dying from old age at a hospital at least.