The general recommendation is to make individual tinctures of each of the herbs in the recipe AND THEN blend them together in the stated ratio " so many parts this, so many parts that, so many parts the other, etc"

Example: lets say you are going to make enough formula to fill ( or come close) a 32 ounce jar, and the recipe calls for "4 parts this, 1 part that, 1 part the other". This requires you to determine what the quantity of a "part" is, keeping in mind you have some flexibility. If you try 1 ounce as the quantity of your "part" for this formula, you will blend 4 ounces this with 1 ounce that and 1 ounce the othet for a total of 6 ounces. If instead you use 5 ounces as one part, you will blend 20 ounces of this with 5 ounces that and 5 ounces the other, totaling 30 ounces which comes close to filling a quart or liter jar.

Good luck.