Right. Aromasin is better than Arimidex and you never want to use Nolvadex. Not only will Nolvadex lower your igf-1 and GH but it can actually promote gyno if you're using a progestin like tren/deca.
I would not dose it EOD even though half of those using it do that. It has a 27 hour half life so using it EOD is going to roller coaster your blood levels. Your body has a hard time dealing with uneven blood levels of estrogen. Use 6.25mg/ED if 12.5mg is too much. But honestly I don't think you should. I think that you should do what others do and use 12.5mg.
No, you can start it the same day you start your cycle.
It reaches peak the same day.
Per week? No.
2.5 per day is the maximum dose that men use. Most men can use only 1.25mg/ED.
AI's do not inhibit gains. This is a myth from body builders who used AI's and didn't get bloated so they thought they were inhibiting their gains. Put that out of you head.
I want to say this again...
You are not using an AI just to keep gyno away. You are using it for your overall health. High levels of estrogen from a Test cycle will cause loss of libido, acne, high blood pressure, fat gain, enlarged prostate, and roid rage or mood swings. It's not Testosterone that causes anger issues, it's the estrogen. You're PMSing, just like a girl. And for the same reasons.
Don't cut corners here.