If something is in CWA then any CWA owner (resale or otherwise) can make a reservation there (subject to availability) which brings us to your 2nd question "How much of any resort is in CWA?"
There is, or was, a "book". another Tugger told me they saw it. I saw it in San Diego, I had caused two salesmen to walk away from me, by pointing out their lies, and finally the sales manager came to the table,,, and we got along really well (actually told the salespeople that there are some owners that they can learn from) In any case, I asked him my question "How many units at La Belle Maison are in CWA? So he got the book and left me alone to review it.. (25% of La Belle was in CWA at that time) . but the exact answer is a moving target... more is being added all the time.
So to answer your question... There is an answer, but finding it will be difficult