Port 465 is the standard port for old-school SSL auth, TLS auth uses port 587 or 25 usually, the guide is wrong in saying that port 465 is used for TLS. Apple Mail does not support SSL (even though it erroneously says it does). However, I highly doubt that Yahoo only supports SSL, because the last clients that did not support TLS were Encourage v.X on the Mac and Outlook Express for Windows.
The cliff notes: try port 587 or 25 (I'd try the former first).