Yeah, so I ended up setting the line height in: Calibre2/resources/templates/html.css
so I have:
p, dl, multicol {
display: block;
margin: 1em 0;
line-height: 0.92em;
}
and then call calibre with just the font-size of 13 - which results in a font-size of 1.0833em, and a ratio of about 85% line height to font-size.
But it sounds like you can still override the font size, you aren't stuck with what the kobo display thing provides?
thanks for your help!