12.5 EOD. I did 12.5 ED when I started to get gyno and when j finished up my joints hated me so much. Even after I discontinued use, I was still suffering 3-4 weeks later
Mast is not an AI, but it does have some AI properties. Even if you are gyno prone the dose of Mast you are running plus 12.5mg aromasin EOD should be plenty.