In the Netherlands and Switzerland, with decades of experience, there has never been a case of someone waking up after drinking 6 grams of N. For some individuals, it may take longer with 6 grams, which is why the dosage has been increased. In Switzerland, now 98% of individuals die within half an hour with 15 grams of N.
In the Netherlands, many doctors prefer oral N over intravenous because it leads to a gentler death, and according to research, death with 15 grams of N is highly predictable, usually occurring within 20 minutes, and it consistently goes smoothly. Numerous articles on this topic have been published in medical journals and in the Dutch media.
I'm sure not much difference between 12 and 15