When I checked which one of the MoCA's are the NC, I realised that in all 3 of the web interfaces, the Network Controller(NC) is enabled.. Which MoCA 2.5, should I assign as the Network Controller(NC)? ( Main MoCA / Office MoCA / GameRoom MoCA )

Another question, I saw there is a Preferred NC option, on the MoCA settings tab, Does this affect / makes a difference regarding speeds ? Could you explain this option?