I'm not convinced of the value of Night Shields on Ravagers. If you have to jink, you basically throw away a turn's shooting, but if you don't jink, the NS only gives you a 6+ save. I have tried placing 1 Ravager with NS in a ruin, so that it has a starting cover save to improve, but doing that sacrifices mobility.
On the other hand, I haven't fielded 3 Ravagers in a single list since the new Codex, so let me know your experiences on the table top.
I am a big fan of the Dark Artisan, but my personal preference is to give them a WWP to terrify my opponent with a precision arrival of 2 high-toughness monstrous creatures.