From the last week in September to the second week in January, BWV will be challenging to book if you can't book until AFTER seven months - i.e. six months is different than seven - even six and a half will reduce your chances. If you can call RIGHT at seven months you'll have some luck - it won't be a slam dunk, but I'd think you'd get a preferred view (not Boardwalk) more often than not.
One thing to remember is that it is within Disney's power to change dates for Food and Wine (or any other event, or add events) - when we bought we bought BW for the purpose of going the week before F&W started - that was when our kids had a break. Well, the year we bought was the year Disney decided to extend F&W and now our time is smack in the middle of F&W. However, now our kids are in middle school and we go in August. If what you want is to make sure you are at BWV and you'd be disappointed with anything else - buy there. If you will be happy with anywhere at Disney, and just would like BWV sometimes, you don't need BWVs.