You can read an insight on your own in your own time and when you get together with your friend or friends then you can discuss it in as little or as much time as you like.
For a more structured get-together I recommend 1.5 or 2 hour sessions; 1 hour sessions do not allow for deep discussions. You may cover more than one insight per session. Also, you can go over an insight in many sessions. What is important is understanding the insights. Some of the insights will be made more clear much further along when reading other insights. So do not fret if you do not totally understand an insight.