Philip, you are asking the right question for speaker wire. According to Maxwell's Equations, two ribbons with wide sides together, are the theoretical optimum for speaker wire. It's the current that makes inductance your main enemy for speaker wire, while the tiny currents in line level cables make capacitance your main enemy for line level. Lower capacitance means conductors further apart.
I have used Goertz, and can recommend it.
I have used Goertz, and can recommend it.