I imagine obtaining potassium cyanate (KCN) in most countries is at least as difficult, if not more so, as obtaining pure sodium nitrite (SN). But I recently discovered that the kernels (seeds) obtained by cracking open e.g. apricot and morello cherry stones in particular can be chewed to release a significant amount of amygdalin, an aromatic cyanogenic glycoside compound, which converts to hydrogen cyanide (HCN) and benzaldehyde when in contact with enzymes in saliva and in the intestines.
Reports indicate that 20 well chewed apricot or 9 morello cherry kernels develop acute cyanide toxicity. I tried 3 plum kernels and detected a pronounced almond or marzipan flavor from benzaldehyde, confirming that my body had produced HCN. Plums, peaches, red and black cherries are less practical as a HCN source, as more kernels have to be chewed to reach acute cyanide toxicity and associated death within "minutes or one hour".
Both SN and cyanide function effectively by hypoxia, depriving the blood of oxygen, resulting in "cyanosis" showing as a blue tinge in finger tips and nails (if not lacquered) and lips (if not wearing lipstick).
The former SaSu member StrawberryPanic documented her SN suicide in a livestream video, dying in around 30 minutes after drinking two portions of SN solution, so she probably ingested less than the 25 grams amount for a quicker death. She didn't show signs of nausea/vommiting, but that may have been due to using anti-emetics, as she was looking for them earlier in a forum post. She smiled several times well after SN ingestion, so was happy at what she had done to herself, even proudly showing her bluish finger tips and nails to the camera, confirming hypoxia was close to killing her. Only just before she lost consciousness did she show suffering (headache?) with a furrowed brow. She seemed to be impatient at it taking as long as it did. But she achieveved what she sought, seemingly peacefully.
By comparison, ingesting a lethal amount of cyanide in one go, so the body can't eliminate it in time, is said to bring an admittedly painful death rather quickly, between minutes and one hour, preceded by dizziness, chest tightness, light-headedness, palpitations, walking difficulty due to nerve damage, headache, abdominal pain, nausea, vomiting (anti-emetics?) and diarrhoea, followed by coma and death. In view of diarrhoea, it is advisable to fast and to wear incontinence panties, which may be needed anyway to absorb uncontrollable urination as body functions start to fail.
Free unrestricted availability of fruit kernels may favour their use for suicide over SN, if the toxicity reports are indeed valid. In the end, it may be a matter of "no pain, no gain), fast with pain, or slightly more slow but peahcefully.