Brother, i'm not trying to be a smartass here. The arguement is that in your case i would try to assess e2 based on bloodwork which you've already done and not in the amount of test. That's what i'm saying. Now, someone mentioned what if you're hyperresponder to AI? I don't know it and you can't know until you try. The only thing i'd say on this is better split your arimidex dose as much as possible. Don't take 1mg at once. Chose a dose and spread it across the week.
Since you aromatise that much if you take lets say 0,25 or 0,5 per week, this might be sufficient to prevent further testosterone conversion to estrogen but since you won't stop injecting test, to actually lower the already high amount of estrogens you will need more. You can find how much by trial and error, there's no other way. You can take it slow, lets say start with 4-5 days a week of 0,25mg and test your e2 after a month and take it from there or you can be a little more agressive and go with 0,25 every day. Just a quarter of the pill with your morning pills or before bed. Then check it after 3-4 weeks and reassess.
If you're planning to stay on a true TRT dose i'd suggest to avoid primo. Yes it lowers e2 but to some people only, some get no reduction at all..so it will be again a period of trial and error to find dosage, getting labs again etc, plus most probably you won't notice any significant difference in that low dose. If you want something extra i'd say to bump up your test dose and AI dose accordingly. Cheers!