Wow! That sounds really technical stuff that only experts can understand, but thankyou so much, David, for that brilliantly written reply.
I'm afraid I am not very technically minded (I wish I was) I'm just happy if something works, or looks nice lit up, or sounds pleasing to listen to!
I know! I'm a duffer!
I do know how to fit a plug really well, though. It's one of the few things I am really good at....