I think your chances are quite good for late August.
My advice is to call MS and reserve the first night as soon as your 7 month window opens. Tell MS that you are considering calling day by day and that your final check out day will be xx/xx/xxxx. Ask what availability looks like for the rest of your reservation. The CM will be able to tell you if continuing to call day by day is you'd book all the remaining days on the day the 7 month window opens for your last night). In either case, the CM will note your final check out date and hold the confirmation letter until the final call.
If by chance some of your days are already completely booked, get on the waitlist - I recommend waitlisting for the individual days. I'm sure the waitlist will come through relatively quickly.
NUHuskies, I doubt you will have any trouble. Schools in the south start back early August, even here we go back the third week or so. Even people who take their kids out of school usually don't do it so close to the beginning of the year. Also, many people may be scared of hurricane season for a while. Good luck, let us know what happens.
I called day by day for my March trip in a 2 bdrm in BCV. Its the week before Easter and its prime season and I was able to get the room with no problem.
I did call day by day though. August should be a much easier time to get a 2 bdrm. I think if I would have waited any longer into my 7 month window I would have been waitlisted.
Thank you all. These are my first ressies and want to make sure I do it right. Taking DSis and BIL and this is her first trip in 20 years, and he's never been and I want things to go well. We have been going the end of August the last few years and never had a problem with onsite ressies but this is different. Last year we were there in between hurricanes and had a terrific trip.