Right Word and Almost Right Word

“The difference between the almost right word and the right word is really a large matter — ’tis the difference between the lightning-bug and the lightning” (Mark Twain).

I would have written “lightning BOLT” for alliterative purposes — so, BUG and BOLT. Mark Twain fain broke off the “bolt” when he should have wrote:

“’tis the difference between the lightning-BUG and the lightning BOLT.”

But, alas. Is Twain’s blazing-across-the-stormy-night-sky omission of “BOLT,” a lightning bug? Is my revision of “BOLT” a lightning BOLT? Or, am I just lost and dazed in a haze — perhaps in an over-analytic gaze —  since Twain spoke of word, while I speak of phrase?