I agree that your chances are good if you place your OGS early.
First of all, AKV is a pretty large resort with lots of owners, so the odds of someone exchanging out are good.
Secondly, although you would think June is a busy time (and you'd be right), once a DVC owner exchanges out, you are not competing with DVC owners for that villa -- only others trying to exchange.
We had a perfect example of that last December. December is impossibly busy, but we were able to get an OKW 2-bedroom from Dec 14-21. And we got it about 5 months out, which would be absolutely impossible for a DVC owner trying to use their points.
If you put your OGS in early, I would put only the type of accommodation you want, and only the resort you want. Don't list all of the DVC resorts because you'll just get SSR or OKW. List what you want and hold out for it...you can always broaden your search parameters later if you want.
I'm not sure if you can do an ongoing search for less than a week -- hopefully someone else can answer that one for you.