How Long Can it be?

How long (how many characters) can the WiFi id/name be (in the PI and the Plus)?

When a user finds Rachel in there Wifi range, they must know to put in / “my.content” - in their browser. Is there a way to make Rachel pop up when they open their browser… or re-route any attempt to go to any common “starting homepage” to the Rachel intro screen? For instance, it the user tried to go to Google, Bing, Yahoo, Facebook, CNN or whatever, it could load a screen that says they those sites are not available and point them to the Rachel home page.