shielded microphone cable guidance

[Princo]

im building a pair of 300b pse mono's and thinking about the signal wiring, input is at the rear and runs all the way to the front, obviously will try to keep clear of any mains/ht wiring.

i have some decent quality 2 core shielded microphone cable lying around which i am thinking of using but need some guidance:

1. just use one core connect to signal in and shield connected to earth and ignore the the other core

2. solder both cores together at each end and connect to signal, shield connected to earth.

3. or forget it and just using single core un-shielded