Couple things...technically, routing changes are not allowed when flying standby. This is obviously to prevent getting stuck at your connecting point with no confirmed onward travel. In practice, this shouldn't matter when changing from a connection to a non-stop but I have had agents refuse to place me on the list citing the letter of the law and force me to wait for my fare class to open for SDC.

With that said, if you happen to get an accommodating agent that is willing to let you standby for the non-stop, you could also ask to be put on the PR1 upgrade standby list as a displaced F passenger. This way you would clear right into F when the upgrade list is run, assuming there is availability. That way you would be ahead of any CPU's but I wouldn't be surprised to see some TOD's fill up the last few seats so I would be prepared to sit in Y if you really want the non-stop.