I appreciate this plugin is focused on the generation, rather than playing, of complex announcements (but the two are interrelated - so here's my query in case anyone can illuminate me).
There is a lot of old discussion on TTS and indigo in across the forums and much of it is conflicting or outdated, so its hard to identify the 'gold standard' implementation if there is one. In addition to the native Indigo capability there are at least 3 plugins (sonos, announcements, announcer) that address it to a greater or lesser degree . There's also conflicting advice on pointing speakers to the Indigo server process; system; and the Play Sounds app as the source of audio (all seem to work actually?).
In my experience with using Indigo for simple TTS announcements, it has always been problematic because whilst testing works perfectly in the real world announcements are often delayed - I think related to when Indigo mac's screen is asleep, though not consistently?? So confusingly announcements may be heard hours after they were meant to be. I'm using a Mac mini running hIgh Sierra for Indigo. Ideally I would want to point the announcements to a HomePod using airfoil, in addition to the internal speaker.
Does this plugin address this delay issue (or does anyone have a workaround for this?).