Arimistane 50mg per day and tapper off slowly after 60 days of treatment, that is a much better way in my opinion as letro is for extreme cases, for you it may become worse and you may experience a rebound.
Your doctor is wrong, as letro will not reduce your E2 levels, it will crash them. It's like one of the most powerful anti-estrogen compounds. Better opt for something much milder and yet effective, such as aromasin or arimistane. Aromasin would give you some very good benefits. For instance, it will increase free test levels and increase the IGF-1 production by up to 25%. Also, it will increase your good cholesterol levels, which is a good thing to get from an AI.