1 teaspoon of tincture per 6 to 8 ounces of potion (OO/GF)
or half a tea bag per 6 to 8 ounces of potion (OO/GF)
or heaped teaspoon of dried per 6 to 8 ounces of potion (OO/GF)
I prefer to use fresh root which grows in my garden. With fresh root I use about 2 ounce, which I blitz in a liquidizer with the lemon juice and then strain rough a sieve.