It really depends on how potent the Green Tea is.
If the Polyphenols is around 90%, then 1,000mg is a good daily dose.
Anything under 90% I would go with 1,500mg.
A good one is Lean Grean by PrimaForce. Only 1,000mg needed with that one as the Polyphenols is 90%. Pretty good Green Tea Supplement.
Be sure to spread out the pills throughout the day. I usually like to take mine right before my major meals.
Hope this helps, and it is only my opinion.