I think that you have to focus on hitters to begin with. RBIs are the easiest to predict. Start with Arod and then to Pujols and etc. Saves should be the next priority because there are only a few guys that are at the top of the list - Gagne, Wagner, etc. Draft for wins last. If you have a top notch lineup, you can keep the same guys in everyday. With pitchers, you can simply rotate in whoever you think has the best chance. You could churn very easily in this league and still get by - usually, it's unethical, but in this case I don't see how anyone could have a different strategy.
If there are a limit to roster moves, however, pick up wins last anyway. You can get a bunch of wins from using your entire bench for pitchers and by getting middle-reliever vulture wins. Not so many vulture rbis out there.