Hello,
Unfortunately with NBE herbs, YMMV (your mileage may vary) applies.
Also, I think the answer depends on:
1. How much breast growth are you looking to attain?
2. Do you have any concerns about having changes with your libido, fertility, etc.?
In general, I think 1,500mg of PM is a reasonable starting dose. Typically I would say the baseline dosage to trigger breast development in genetic males would be 2,000 mg. I've certainly been on much higher doses (anywhere from 3,000-4,000 mg per day) before I finally made the switch to HRT.
While this probably isn't the answer you would like to hear, I think it's best to be patient with NBE. Give your body time to acclimate to PM and whatever other products you may be using. Using too much PM can be problematic just as using too little.