on the doses you're using, I really wouldn't bother using anything for gyno.
but, since you already have gyno, I'd say try starting with 10mg/day with the nolva and see if it improves.
I've known a lady who started nolva at 10mg/day as part of the first phase in breast cancer prevention/treatment (she didn't have breast cancer, yet, but she had the gene and her sisters/mother/aunts died from it.. it was a preventative measure before her double mastectomy)
she started with watermelon tits, mayne a lil smaller... after a couple months, her tits were down to large grapefruits.. allllllll with 10mg/day nolva. she was pre-menopausal, so no arimidex.