I have been able to determine (using online dosage calculators) that the correct amount is indeed 8 units, as determined by weight of the snake and desired concentration of the medication on hand. I don't have any guarantee that this is the correct medication, because I am unable to culture the infection. I thank all of you who offered your advice, and I hope that I will be able to participate in more conversations in the future. I'll post an update with the results when I have some.