"What chooses to be less ego and more witness? Does the ego decide, in essence being complicit with it's own demise? Is it the witness itself? that doesn't seem right as the witness just witnesses. So is there some other part of myself that "chooses" who is behind the wheel?"
Nothing chooses to be less ego and more witness. Witness is our true nature as pure awareness. However, we are caught ordinarily in what we are aware-of -- awareness of separation from others; awareness of the world; awareness of wars and news and so on. We can put it this way -- you are a human being. The human is what you are aware-of (mind). 'Being' is pure awareness itself (the witness). Since Being is what creates and makes manifest the human, it is also its controller. When we start recognizing who is the driver (pure awareness) then we automatically become more aware of the witnessing part of us. This greater awareness of itself becomes a major fulcrum of our daily life and thus becomes more prominent. This greater focus on the witness automatically minimizes our ego's control thus there is less ego as we see that the witness is our reality. There is no chooser or 'doer' but only 'seeing' more and more into what truly IS!
The ego doesn't decide, it simply chooses automatically from its past experience of fear. For example, you see a very attractive girl and you are drawn like a magnet. The ego will remind you that such an encounter in the past ended in disaster and it might happen again and all of a sudden there is hesitation, uncertainty, even fear. Our natural tendencies get thwarted by the ego's past experiences. Thus, when we do not learn from ego's past we tend to let the ego 'decide' for us. However, when we SEE clearly that the ego is just fear then it loses its influence and we are freer. The ego never decides for greater love or joy but only offers protection. Here's another example, let's say you love dancing and the last time you were the only one on the floor and for some reason you made a fool of yourself. Next time you try to get up to dance and be the first one, the ego will try to protect you against embarrassment. Whereas your true spirit of BEING is more spontaneous and egoless in its pure enjoyment and therefore takes chances. The ego only seems to decide when there is fear of being fully yourself and then tries to protect you by increasing your uncertainty and lack of self-confidence. The ego protects to increase its power and also protect itself from dying. The ego dies when confidence, courage and love take over.
The witness is the driver but sometimes gets twisted by the ego's interpretation. For example, let's say you want the truth of your being and therefore sit still, relax and enter the vast space within you. It will feel peaceful and gentle at first, then the ego gets frightened of its own demise and starts protecting itself by turning this vast space within into a very dark emptiness and a frightening abyss.
Actually no one is behind the wheel doing the driving but Oneness itself. Everyone of us gets driven according to our capacity and readiness to see. The more we see, the greater becomes our freedom and joy.
There are over 6 billion humans on this earth, but there is only One Being, One Awareness, One Witness playing all the roles of the 6 billion humans. Each human evolves at its own pace according to its ability to 'see.' It is all quite perfect in its grandeur.