After a great meeting over the weekend, I'm now back where I started.

It would appear that the "standby" and "fly now" options are both made available at 12AM on the day of departure on the website, irregardless of how early the flight may be. When I logged on after that time, the site offered to list me on the 5AM flight out of GFK (no thanks!).

In any case, the standby game worked out perfectly for me...made both earlier flights and arrived at my destination two hours early for a change.