The different shades of gold?

Greeting everyone.

Once again, I pose alloy questions as I am trying to assemble an alloy list (much like someone else on orchid :wink: ) This time my question is this, for Yellow gold what sort of mixture of silver and copper yields the most pleasing shade of yellow. I would like a shade that is both rich but not dark and without any pink undertones. In other words I would like a neutral medium yellow colour. I assume a 1-1 silver copper ratio added to the gold achieves this? Or does it change depending on the karat 14, 18 etc. Any input is helpful and thank you all for the responses.