A minor point, but all my options have 4 receivers, not just Option 1. Anyway, thanks for the clarification. I understand where you are coming from now. A bit of over-engineering is better than the alternative and I'm a 'belt and braces' kind of person myself (suspenders have a different meaning this side of the pond!).

However, I have just completed installing 18 awg for the emitter runs and Cat 5e for the receiver runs. Given your comments, I might install some more Cat 5e.