No most men need to take say .25 mgs in your case .25mls every 2 to 3 days it takes 5 weeks to build up in your body and the half life is 3 days. Gage not going to low by your night time and morning wood. When I got my Estradiol down my wood came back when I went to low I lost it. So if you lose wood stop the Arimidex until your wood comes back that day go back on it but do less. I do .25 mgs every 3 days some times this in not enough so I go on every 2 days. Estradiol is the hardest hormone to control with your older and or on TRT.
You need to keep a log how you feel when your to high or to low. If your levels are to low you can't get it up taking Viagra. If your levels go up to high as they are going up I get sore and hard nipples low grade wood and look red on the upper parts of my body and head. So between labs and wood I keep my levels good between 15 to 20 pg/ml if your SHBG is on the lower side say 20 to 25 you need to keep your Estradiol lower say 15.