i also have gyno and once you have it, it becomes like a 100 times easier to aggravate and grow. so no matter what if i were you, i would have an AI and run it continuously threw the cycle maybe even start it a week or 2 before you begin (you can never be to safe when it comes to gyno. ive never used aromasin so i cant comment there, ive always used letro which i would highly recomend.
also masteron was origanlly made for women with breast cancer i believe and has slight AI properties itself, but still you should run an AI. and i agree if you may get shutdown from the danazol you might as well use the time to cycle, eventhough the gyno reduction will be less effect with the extra androgen. but really once the lump is there its there. but you may get some shrinkage. it always seems to me that if im not running an AI my gyno is always somewhat aggravated and with letro the aggravasion goes down and so does the lump. which is what most people i think interupt and it shrinking but its more your just stop aggravation if that makes sense. good luck