Briweve, there will be some estragen in your body even on non-aromatising aas, even in the even of heavy htpa suppression. As far as progesterone converting into estragen, I don't know. I'll look into that. Progestins (such as tren and nandrolone) can increase estragen receptor sensitivity, which would make even a small amount of estragen more effective. At his dose of tren, the winstrol should be sufficient to prevent gyno, however a tren/winstrol only cycle will have a very negative effect on one's lipid profiles, and the nolva should help to alleviate this problem. There are some guru's who have theories that trenbolone can be a weak agonist for ER's in some individuals, in which case nolva would be a godsend for such people in preventing gyno.
jubei, if you are going to stack hcg in with your tren (which I don't like the idea of) you would be wise to use aromasin or letro in addition to the novadex. hcg will greatly elevate estragen levels, and this is not desirable when on tren. It will also defeat the purpose of a tren/winstrol stack, since I assume you are lookign for pure lbm gains with no water retention, and increased density from such a stack.