A bit of a coincidence here. I have been considering speaker cables for my C1s for a while. I just got three cables from The Cable Company and started listening. The three cables:
Synergistic Research Tesla Accelerator
Nordost Heimdal
StereoLab/Stereovox Diablo LS
At this point I have listened for a couple of days to the SR's and I am listening to the Nordost now. I have not tried the Diablo's yet.
I have a Simaudio I-7 integrated and SuperNova cd. I am using a Nordost Heimdal xlr interconnect. The SRs are smoother and a bit fuller in the midrange. The Heimdals are seductively detailed, yet not as full bodied (for lack of a better way of putting it).
I have had a Plinius 8200 MKii in the past with Dynaudio Contour S1.4, so I am aware of the differing characteristics between the Plinius and Simaudio. It is interesting that as I was listening to the Heimdals this morning I thought they would make a good combination with the Plinius, but at this point the jury is still out on the Sim- Heimdal match.
Your amp/ speaker combo are of sufficient quality to merit working with The Cable Company to try cables out in your system.