I noticed that there isn't much help for Mac users an streaming on Picarto so I thought I'd write up a few quick notes of junk I've figured out.
Use OBS not Wirecast. Even if Wirecast was free (it's $500) it's almost feature for feature worse than the free OBS. The only thing that wirecast had that I miss, a preview window for scene switching, and it allowed you to capture sections of desktop.
OBS is not going to have sound support for desktop audio out of the gate.
It's listed on their known Mac issues.
I've switched to using sound siphon
It works so much nicer, not as buggy, and is actively supported.
You can mute or change the audio your listening to without muting or lowering the volume for the stream, and you can have specific apps send audio and have other