I've added some missing posts and topics which I could retrieve with mysql matching and parsing some cached search result pages. It's not much, but I'm not expecting a lot of lost posts anymore. There's now 99,000+ posts restored, which is more than I hoped for.
I've also worked on cleaning up some UTF-8 problems, which are gone now for the topic-titles and post-subjects. The forum texts themselves still have some strange character encodings, but I expect to remove them the coming week.
I took a look at Adam's adjusted modern theme, it looks good. The classic theme too, by the way.