There are some really wonderful spiritual directors who are Presbyterian, but I don't think that should be a requirement, because if a person is truly listening for the movement of God, they are listening beneath all the externals. That is where the encounters with the Holy occur. And in fact someone from outside one's own faith tradition may look at things totally differently thus giving a person a whole new arena in which to move. We believe God is revealed in ordinary life. God is active and discernable in all human relationships, structures, and ways of living.
Spiritual development involves all of our experience.
Spiritual direction helps people notice God in their current reality and make free, life-giving choices. There are as many different styles as there are folks. The core is allowing space where God can exist and where the person can reverence their experience, their encounters, and their questions. Spiritual direction is really allowing the director or the companion or the spiritual friend, to use Kenneth Leech's term, to get out of the way so that the wisdom that is God within the directee can emerge. The directee slowly will be able to first acknowledge it, then embrace it, honor it, and eventually reverence it.