Analogy: "as if" vs. "as though"

This is something that confuses me from time to time. When making an analogy in literature, is it better to use the phrase "as if" or "as though", or is it completely a style thing?

E.g.

She looked frazzled, as if she had just gotten off of a roller coaster.

or

She looked frazzled, as though she had just gotten off of a roller coaster.

Solution 1:

Garner in Modern American Usage (p67) has an entry on this. First he claims:

Attempts to distinguish between these idioms have proved futile. Euphony should govern the choice of phrase.

He then goes on to state:

One plausible distinction is that as if often suggests the more hypothetical proposition when cast in the subjunctive <as if he were a god>. ... By contrast, as though suggests a more plausible suggestion <it looks as though it might rain>.

However, I see no distinction in suggestion or meaning between the OP's two sentences.

Solution 2:

I thought about this for a bit (maybe too long) and started feeling that "as though" seems to work better when addressing a condition. "It looked as though it might rain."

And "as if" works better when concrete situations/options/determinations can be considered. "It looked as if the game might be called off due to rain."

The difference is subtle, but it somehow gets clearer when you consider the effect of using "even if" or "even though" on similar phrases.

As though it really matters. As if I really care.