Brother Letrozole/Femara is the biggest baddest AI around. IMO it should be used with absolute discretion and only in cases where gyno is present. Are u having advanced symptoms? Do you have Aromasin or Adex on hand? Whenever I run a big cycle upwards of 2grams I would run an AI like Aromasin from the beginning of your cycle. With dosages that big I wouldn't run Aromasin any lower than 12.5mg ed. I would start there unless as I said before only if advanced symptoms are present.
If Letro is a must try this site's protocol for gyno.
http://www.basskilleronline.com/gynoprevention.shtml

Use Letro only as symptoms are present once the symptoms lessen use an AI like Aromasin or Adex. Running big dosages like u are you want to get maximum gains for your money's worth.

that stuff is not good for long cycles cuz its harsh on lipids. I say since ur sensitive with estro n ur running 2 grams of gear use 12.5mg exemestane if u get estro prob still bump it to 25mg

why are you choosing fem bro. its main goal is to eliminate estrogen. where adex is more a blocker (we need estro to grow) @ 2g a week i guess youve done it before but fem will be a shock to the system. they generally come n 2.5mg tabs so cutting them up will be a bit*h but if you are going to run it id say .25mg twice a week.. ill let others answer this one though..

use femara at the lowest dose possible bc it cuts out ALL estrogen and if you cut out all estrogen it isnt good bc you need just a little bit to grow the best possible and be the healthiest ass possible. Not too much but not zero either. Ive used it at the min dosge eOD and was about 1.5 to 1.75 grams per week with ZERO estogen sides.