thank you. I have actually read it, but it is still quite intro level, right? I am interested in best practices , how to deal with errors, gotchas etc...

Perhaps there is no such text and Tim Baldridge's videos er best?

not aware of anything other than Tim's videos

One of the things I bought “Clojure Applied” for was that it wasn’t intro. wrt core.async, it goes beyond the high-level and minimal example cases, showing its practical use in a number of situations.

that is right but I want something even more in depth

in all seriousness: you should write it! i’d pay for it.

core async koans!