Nice catch Leigh
I always look at a star first...you can get a good idea of the seeing by watching one, apply a little defocus so you can see the rings, then watch how much fire there is...if it's a little too fiery, I don't bother, although you can sometimes still get some interesting data at f/10.
FWIW in my limited experience, I've found the nights of better seeing in Brisbane to be hot summer nights. Sounds counterintuitive, but that's just what I've noticed.