I would start out with the AI. Its going to help keep some of the test from converting. I'd just be sure to keep it low. .25mg EOD should be good. Remember that the HCG is going to instantly spike your test levels and also create estrogen. These sharp spikes can produce gyno issues but with the adex, you won't have to worry about that. If you find you need a little more, you can always bump it up to .25mg ED. Plus, Test is going to want to copnvert to either estrogen or DHT. If you block DHT, there is a chance that more of it would convert to estrogen.
With finasteride, once you start taking it, you are suppoed to coninue on it...until you don't care about keeping your hair anymore.