As an ancient one I'm from the days when high end speaker cable was 14 gauge lamp cord rather than 16 gauge. It took me a while but there's no question different cables sound different and they probably vary depending on the rest of your system, especially the amp/cable/speaker combo. So I believe a lot of experimenting is needed(and cables are often costly).
By the way if the amount of copper mattered then the old Fulton Gold cables had to be the best. You could jump a jet engine with them. They were good and definitely not bright due to high inductance rolling off the highs a bit.