We're still well before the 7 month window, and ressies at BCV are becoming difficult to get as well. Days are "spotty"...you might be able to get one night, but not the next two. This is for ALL size rooms. I don't think there will be much available by the time the 7 month window rolls around.
There are two issues. Time of year (your question) and room type. 1BR are easiest to get but perhaps that's not what you want. Perhaps you want a std view studio at BWV but all you can get is a preferred 1 BR. Technically not sold out. All the resorts (except SSR) have room types that are in demand all year long. However, that doesn't mean you can't get them at 7 months but.....
Generally, the most difficult time to book at all resorts is the first two weeks of December, Christmas week, Easter week, and during the food and wine festival.
As others have said, certain unit sizes at certain resorts will be more difficult too.