Like you I have a low power, high efficiency system, with fully horn loaded speakers. After playing with various cables including Duelund, which I found charming but ultimately too colored for my taste, I’ve now found audio nirvana with some "Chinese Valhalla" (in truth a chinese copy of Nordost heimdall). There are no logos or fake branding but the cable seems identical.
They are the best cables I’ve owned: not thin at all, nor bright (and my system is on the bright / upfront side so I should know!) but very dynamic, transparent, and wide open (imaging is fabulous)
It’s been compared by others to entry level Nordost stuff and is better, doesn’t have the "thin and bright" character at all. In fact I find it buttery smooth!