Drove it home today (surface roads, about 8 miles), temp stayed normal (around the unmarked white line) but I had the A/C on the whole way. When I let it idle after arriving at home, it got up to just about the 220 line without the fans coming on, at which point I gave up and shut it off.
Next week I'll try bleeding it and see if that helps. Ryan F (hippieman9 on here) sent me some instructions so hopefully I'll make less of a mess of it than I did last time.