Hilton Head is very difficult to get at 7 months during the summer.
Beach Club is difficult to get at 7 months pretty much year-round.
BWV and BLT not terribly hard to get, but only the BWV Garden / Pool view and BLT Lake View. Other views more popular with owners and not likely at 7 mos.
That's the best answer I can give for such a broad question. In 10 minutes a poster may come along claiming he had "no problem" booking summer HHI or BWV Standard View, but overall I think such success is unlikely. Exact experiences will vary greatly from one week to the next, different room sizes, different years, etc.