I wrote a little bit about this topic on here, since this was what I pondered about as well.

viewtopic.php?f=7&t=16784

There is a split and then a merge.

Self inquiry is how we sesparate into the observer and the observed--the two "I", doing interacting probing to get to the core. OBE is also preceeded by this process--maybe not probing, but the observer and the doer.

With a common goal and intent of experiencing true self, the two routes can enhance one another.

To achieve it more often, OBE has a more specific technique to do.

I have been focusing on the experiencing of my own truth by meditating in the nature, getting more familiar with how to face with the non truth part of self. Even without the intent of an OBE, meditation will no doubt cultivate more energy and its movement in our body. When enough is accumulated, the excessive energy can trigger an OBE.

This is just my two cents.