well if you adding the thc thc to the butter/chololate then use ratio portions. eg. 28 grams of cannabis per 28 oz of butter.. then you have 1g per oz of butter/chocolate so of each batch of cookies gets 10 oz of butter and the batch makes a dozen cookies they will each have just under 1 gram per cookie

if you butter/chololate came with the thc in it already then idk.