Q: How to avoid getting bogged-down with trivial details (“bike-shedding”)?
A: Keep each topic discussion fairly brief, around 15 minutes works well for most topics. If you find a discussion is getting bogged down, you should try summarising, seeking agreement to any decisions required, and allocating actions. In the case of more technical/specialised discussions it might be useful to form a sub-group who can resolve specific issues and report back to the next wider group meeting.
Also, follow good time-keeping practice so you know when you need to move on to the next topic.