usually it is recommended you take 20-40mg a day for the first 7 days then, 10mg/day until your cycle is over. At your doses 20mg should be fine, but personally i like to do 40mg for a week no matter how much gear i'm on, just because i'd rather not be a cheapass w/ tits, and don't want to take chances =)
Also you can use the nolva if you start to feel bloated or holding an excess amount of water. Being too bloated just makes you feel like ****, and makes you not wanna eat, and eating is probabaly the most important thing. High blood pressure is another reason.