5-MeO-DMT = 218.30 g/mol
HCl = 36.46 g/mol
5-MeO-DMT HCl = 254.76 g/mol = 218.3 + 36.46
218.3/254.76 = 0.85688491128
Max yield is 85,6mg from 100mg
Given the fact that your starting amount is tiny mechanical losses will be extreme.
Also did you ever try to google? You dont need to ask here when you just spend 5 mins on google.
IIRC theres exactly the same question on the forum and i already replied there too.