I suggest wait listing day-by-day.
And hang in there. My experience is that you'll get the days you want, though you may not hear until the spring.
This made me wonder if there was a poll out there of people who book only for "insurance dates" knowing in advance its unlikely they will use those dates, bu tthat it is better to have something than nothing. Summer is a time for this, in my opinion. SO many people on vacation and things change all the time, jobs, school, health, other opportunities, etc.
Anyway, get on the wait list, give them all your preferences and wait for your call. You'll be glad you did. HHI is our "home" and, IMO, by far the nicest of the vacation homes.
Enjoy!