Nozzle torque spec

Anybody know what the torque spec is for tightening the nozzles onto the extruder head or where I may find the torque spec? I ask because I’m always afraid of over-tightening the brass nozzle and sometimes it’s harder to tighten properly due to melted plastic in the threads. If I had a torque wrench to tighten the nozzle properly every time, this wouldn’t be a concern anymore.