What are the rails best practices for structuring actioncable channels?

Question

I am creating a trello clone, and want to integrate action cable. I have a main board view that multiple people can be added to. I want to establish a websocket connection for live updates. How should I structure my actioncable channels? Should I:

1. Have a single board_channel that includes all the aspects of a board
2. Have a board_channel , list_channel, card_channel, appearance_channel (active users), notification_channel ...

Is there a performance benefit for splitting up channels? What are the rails best practices for structuring actioncable channels (Matching activerecord models, or grouping to match views)?