It depends on what you are using it for.
If you are using it during your cycle to ward off gyno problems then you could probably get away with 20mg/ED.
If you feel the onset of gyno are have gotten gyno then 40-60mg/ED.
If you are using it for post cycle recovery then do a search, I don't want to quote you the wrong amount and I'm too lazy to do it cause I'm leaving for the day.