Got it running yesterday, everyone in the lab loves it. Had to ask IT nothing, which was a win. Only thing: I first used status=active and it kept repeating acknowledged alarms after a restart because my seen-set was empty, switched to OPEN like you wrote. Also had to change device names from “frz-03” to “freezer three” because piper read it as “frz”.
Timestamps in UTC or it didn't happen.