My thighs went from 25inches to 27 a couple of years ago with GVT and I was natural-it worked for about 2 mos then I started to feel overtrained. I can't imagine what my results would have been if Id been on gear. If you havent tried GVT I suggest it if your not predisposed to overtraining-I cant wait to try it while on.
It depends what bodypart im training on how many sets i do. If i do bis then its normally 3 exercises 3 sets each. If im doing back i do about 6 exercises 3 sets each, so i can hit from different angles etc. If i do more than that i start to overtrain so i try to keep them really intense.