It takes a few weeks for the Test to build up in your body to full concentration strength. If you start on day 1 of your cycle with .5mg/ed of Adex, you're going to crash your E2 and you'll feel pretty crappy. I would recommend that you start your AI on your 3rd week, if you're running a long ester'd Test and on week 2 if you're running a short ester. Run the Adex at .25mg/eod and do a mid cycle blood test at week 6 and make adjustments to your Adex.
Just be sensitive to the way you feel. If you start to feel a lump, then increase the dose. Over medicating the Adex from the beginning is just as bad as not taking an AI.