w00t, got my font sorted out. Had some stupid where trying to apply css to someone else’s code meant I was getting some errors, but managed to suss out where the problem lie and get it close enough.
It would be really nice if the preview also used my custom css, so I could see my post in progress in the ubuntu font too, and with my paragraph indents and all that shit. Oh well, that’s what the preview button is for, I guess.