I really like this question. Not so much because I actually have a useful answer, I don’t really, but because I like where your head is at. Taking two seemingly disparate practices and trying to merge them is like the holy grail of spirituality.
In this case watching vs. acting. What I like to do personally is to merge by not merging. Watch when I feel like watching, and act when I feel like acting. There is plenty of time and space when you’re not watching or acting, that’s prime time to reflect. Go back over your earlier existences and reactions and actions and ask yourself how you could have done better. Keep asking yourself questions and see how deep you can go.
Eventually you’ll start to act naturally in ways that reflect your watchful state. The distance will close and you’ll be able to exercise both aspects of yourself simultaneously.