Have you considered leaving SSR for now, booking the two nights at either BWV/VWL, and waitlisting only for that only night? One night is always easier to get.
SSR will have The Grandstand opening for more space soon so if that didn't work you might be able to switch it all back over to SSR further down the road if the one day never came up. Risky I know.....
As for the waitlist I"ve done it three times and all three times it came through. Might have been lucky. And of course there is always a chance of "nada" but best of luck to you.