Advice on apostrophes 'n possessive

http://www.theglobeandmail.com/news/arts/russell-smith/for-goodness-sake-when-do-we-add-apostrophe-s/article2125338/

To answer the name question first: It varies. Some journals use the apostrophe alone, with a singular name ending in s, some use an apostrophe-s. I vaguely remember being taught to avoid the possessives on names with one syllable (“Keats’ poetry”) and to add it to multisyllabic names (“Davis’s hernia”) – or was it the other way around? Some houses do in fact have variable rules within the same publication. Jesus and Moses, for example, and Greek names such as Ulysses and Socrates, are often exceptions, and are written in their possessive forms without an extra s (“Jesus’ name”, “Socrates’ argument”). The Globe and Mail is admirably consistent on this one: We add the logical apostrophe-s to everything,

But The Globe and Mail’s style guide also notes that recasting these sentences to avoid too many sibilants can itself end up in awkward contortions, and that it is preferable to write “the hostess’s gown” than “the gown of the hostess.” The latter just sounds stilted. And there will always be exceptions to everything: When it comes to odd team names like the White Sox, we don’t add an extra s for a possessive form; we write “the Sox’ losing streak.” How is it possible to keep all this straight?