I would never buy cables without trying a full set - speaker and ICs - in the system for a few days. I can imagine this will be a problem to you, as it is for me - due to customs it is not possible to ask for loans from the US. It is why I am currently looking mostly at European manufactured cables or cables with local distribution.
I am currently using the complete set of the Crystal Dreamline - full bodied, plenty of detail and air, never fatiguing. But it does not have the slam and energy of the Valhalla1 or 2. An excellent match with the Audio Research, perhaps too warm for the conrad johnson's.
Long ago I had great experiences with Avalon and Audio Research using the old XLO signature cables - the grey/purple Signature 5.1 was even more stiff than the Van den Hul Cumulus I am trying!
+1
The only way to truly audition cables is with the full loom. Not all cables will integrate well when mixed. Sometimes you may get lucky. But you can't truly tell which cables are improving or degrading the sound. All the cables interact with each other. We had tried integrating a MasterBuilt power cord on a preamp where the 2 mono-blocks had another brand of PC's. The sound went for the worse. It was only when all the PC's were replaced with the MB cables that the sound was best.
So just because someone pops in an interconnect in to a system with other cable brands and the sound go's for the worse, it doesn't mean that the interconnect is not as good or better than the cables in the rest of the system. They all effect each other.