I used to have accounts with Torzon and Kerberos. I never bought anything. Neither sold Nembutal in a pure enough form. It was either useless micro doses, or instead, useless micro doses mixed with macro doses of other garbage. The closest I got to the real thing was on Kerberos, where I found somebody selling the original drug as they stole it from CEVA. This was the original Pentobarbital drug and not the common Pentobarbital Sodium knockoff on the market today. But they sold in the ridiculously small packages and my even smaller apartment mailbox wouldn't fit ten of them. So I quit looking in this direction. I encourage all people to ignore Philip Nitschke and Exit International because they are useless and outdated.
I don't know much about Sodium Nitrate, other than that sometimes people use it for positive things, like food preservation, or stopping cyanide poisoning. My instinct is that if the man said he changed the concentration to 0.6%, then he is telling the truth, and he had to do it for legal reasons, and buying this from him would be worthless.
Crazy that the stuff you can use to kill yourself is already in our food.