Okay, after some experimenting I figured out:

a) The serif not taking was a display not refreshing thing.

b) Hanging indents don't work, or at least are pointless, on text where each stanza is a p/pre with lines broken with br.

c) Serif is working better for me for editing existing ePub files than Calibre, but the latter still has some uses.

d) That white-space + word-wrap hack is shiny. (I'd not met those attributes before, not having actually studied CSS3.)

Thanks -- this has been most helpful.

---L.