Can you cite to these scientific reports? Link?
IMO, the critical issuance is whether you have developed a tolerance or a cross-tolerance to barbiturates. Since barbiturates are no longer prescribed, any sort of direct tolerance is unlikely. I have read that benzodiazapenes and alcohol are both central nervous system depressants and therefore could potentially introduce some cross tolerance. I am a little bit worried about alcohol as I drink a reasonable amount and have pretty good tolerance, but am hardly a drunk. I just drink daily with dinner. So, not sure how to evaluate for myself.
Nitschke and Stewart3 state that the oral form of Nembutal sold in 100ml bottles (sterile bottles) at a concentration of 60mg per ml (i.e. 6 grams in a bottle) is enough to provide a peaceful death, although in some cases this can take up to 24 hours. For powdered Chinese Nembutal which is sold in higher quantities, 10grams dissolved in 50ml of water is suggested, and forum posts suggest this is a more reliable dose whilst also being easier to ingest. They recommend ceasing any other medications a few days before taking Nembutal. There is also non-sterile (green coloured) Nembutal that is concentrated 300mg per ml, in which case a 50ml sample equates to 15 grams, and is more than enough for a peaceful death. Compassion in Dying5 recommend 6g - 9g of Nembutal. Dignitas use 15 grams of a concentrated soluble form of Nembutal that can be swallowed in a few mouthfuls.3, 6