How Much Ammonium Chloride for Home-made Salt Licorice?
The percent of ammonium chloride listed is in regards to the total weight of the ingredients used. After making a few batches, I have found that adding the ammonium chloride along with the sugar offers great results. Finally, here is an equation to figure out how much ammonium chloride to use, given you know what percentage you want to have:

K = Known Weight of Ingredients (Everything in the recipe except for Ammonium Chloride)

X = Weight of Ammonium Chloride

Z = X's % of Total Weight of Ingredients expressed as a decimal (e.g. 0.06 for 6%)

T = Total Weight of Ingredients

Step 1: T = K / (1-Z)

Step 2: T - K = X

Step 3: Make some salmiak licorice.