Zoltars used to be super-predictable and posted almost every day. After doing >10,000 of them, I can do them in 10-30 seconds each and really the main rate-limiting factor is the load-times of the web pages.
Eventually, Z's went on a long hiatus. After a few months a huge batch randomly dropped in the middle of the afternoon and I realized then, that the only thing good about Zoltars was their predictability and the fact that when they typically posted early in the mornings there wasn't much else up worth doing... But when other HITs are available, they're not really worth it.