Do you have any hard evidence for this at all? I'm not a stonehenge expert by any means, but if memory serves the trilithons are in a horseshoe shape, not a full circle, which doesn't fit your theory of a carousel.
in my thesis on he site http://granaryatstonehenge.org you will find how the trilithons were used in the mill concept and why a horseshoe arrangement worked well for this.........clyde