Club level rooms pop up all the time.
We stay Club level once a year, just 1-3 days, most likely just a single night. More than that would be a waste of points (if you ask me) On checkin day we try to arrive early or no later than 1-3pm and then utilize the lounge throughout the day. On checkout day we do the same, and depending on when our next room is available we stay until late afternoon. On our last stay, actually during this July we had an offsite stay booked at the Sheraton Vistana after Club level and talked about going back in the evening just for food, desserts, ice cream, and free drinks - we end up not doing it, but its an option as you have lounge access until 11.59.59pm on checkout day.
You might not get 3 or 7 days for that matter but 1 or 2 days can definitely happen. Just put in your waitlist no later than 7 months out and you are good. Any closer than 7 month will decrease your chance as others might already setup a WL for the same dates.