Hi, couple thoughts.
For our meetings we’ll use a live etherpad as a simple tool for people to text chat (see right hand side) and ask questions + add discussion items while remaining muted. You can actually embed these into your Discourse forum with this plugin. We find this method better than Zoom’s built-in chat, which is most useful for direct written responses to a speaker.
We always ask anyone not speaking in a room remain muted at all times. Best way to do this is by only using the “push to talk” feature.
150 people is a ton so ask silent listeners to turn their screens off in the event performance slows.
Hope this helps. 