GBC is a 6 conductor 12awg.
Slate is a 8 conductor 12awg.
I suspect that Slate is going to be better because it has one 20awg Perfect Surface conductor. GBC only uses LGC long grain copper conductors. I looked at those slate bi-wire. It appears that they have the silver plated bananas, so keep that in mind if you are critical about termination type. Long lengths don’t come up for sale too much. If you’re patient, you may be able to get a Audioquest Bedrock (which is better still).
Slate is a 8 conductor 12awg.
I suspect that Slate is going to be better because it has one 20awg Perfect Surface conductor. GBC only uses LGC long grain copper conductors. I looked at those slate bi-wire. It appears that they have the silver plated bananas, so keep that in mind if you are critical about termination type. Long lengths don’t come up for sale too much. If you’re patient, you may be able to get a Audioquest Bedrock (which is better still).