From what I understand, there is no magical time that you'll start seeing signs of gyno (ie it could be the second week or the sixth, or not at all), it's largely dependent on the individual. That's probably better, since if there was a standard time that everyone knew gyno would show up if it was going to, you'd probably get a lot of paranoid people around that time popping way too much AI and seriously cratering their estrogen.
All of my experience is with Adex. As far as dosages, if I actually saw signs of gyno, I would start with .5mg of Adex EOD (.25 ED if you prefer). Then there's nothing to do but see what that dosage does and gauge from there. If symptoms don't go away, increase to .5mg ED. If symptoms do go away, I'd stick on that dosage for about a week and then lower it slightly (.25mg EOD) to see if gyno stayed away. If it did and you knew you just needed that mild AI, you make sure not to waste any potential gains with the .5mg EOD.