Split Auth & Game isn't really anything special, for most people its useless. You won't be able to access any auth data unless you come up with a method of transferring it, (either a custom packet or use of the auth responce packet), the only real advantages of having it seperate are; being able to host an auth server anywhere that directs the client to a game server anywhere, your players can have a character on different servers using the same acc and you can host more than 1 game server using the same database and Authentication server. Personally its a waste for me cause I only really need 1 server but I decided to do it for fun cause its something new :P. Even now that i have my server base finished im not using more than one, i may employ a replica of my stable source as a test source, keep my official up test stuff in the test server then transfer to the official if im satisfied etc...
Sorry for typo's my fingers are cold and its delaying my key typing speed