Very slim for summer. You're pretty short notice at this time. Most Westin exchanges go through their points system and the rest are more likely to end up in RCI than II. I'd add 2004 to your list if you can. Look for a direct exchange.
We stayed there in July but did not use DVC points. The property is beautiful as is the island. I was not impressed with the dining choices at the resort but there were so many wonderful restaurants on the island to chose from that I was almost glad.