any benefit in a double bi-wire of 8TC?

You might even try a double-bi-wire set of 4TC. For some reason, 4TC sounds completely different (WAY better) than 8TC in my set-up.

In case you want to know, I'm using a NAD 304 integrated and Triangle Zerius 202 speakers.

...And a single-run of 4TC (bi-wiring, while necessary with my B&Ws, doesn't seem to make a difference with the Triangles).

Good luck!

The 8TC bi-wires are nice and do clean up some of the sound. However, at the retail price it is painful...
I sold my 8's, kept my single wire 4TC's and spent the couple hundred difference on music.

Talking with Kimber Kable they told me the best sonically sounding version 8TC speaker cable is the internal bi-wire version. They got into technical detail and says the coherent signal path is created equal which perfectly matches the impedence.

The only way to know for certain, is to try it on your system/listen for yourself. In theory- It will provide cleaner(more faithful to the recorded material), improved sound, which of course: some don't like(not their taste). Anytime bass is increased relative to the rest of the audio spectrum, the "rest" will SEEM attenuated. The up-side of purchasing used Kimber products is that, should you not like the effect; they can be resold at little(or no) loss and usually- quickly. Keep the runs the same length(hi/lo, same channel), to avoid any imbalances.

I tried that once and it was too much bass emphasis at the expense of upper midrange and highs. Really changed the perspective of the presentation for the worst - a single run of 8TC was much better. Now if you want to get creative go to audio asylum and search 8TC - they have some interesting ideas...