hey, I recall my own exact interlude; in 2005 where I bought a pair (2 sets) of $34k list price ($64k!!!! list price) TA Opus MM speaker cables for bi-amping my VR9SE's with a pair of dart 108 stereo amps. seemed like a fun thing to do at the time. I was throwing money at the system instead of understanding the room and related issues.
of course; looking back I had much to learn and a long way to go......but at that time I was living large.
My own experience with Opus cables - we should not think about throwing in a speaker cable in a system unless you have a source Opus cable. Many people become disappointed with network cables because they do not follow manufacturer rules and mix cables using them like tone controls as you previously said. I have used Transparent Audio cables with great success in different systems, but always using complete looms properly tuned. In my case it was not fun, it was success and enjoyment.
Using them with Dartzeel was surely an adventure, as their equipment is optimized for proprietary cables.