@tomthiel Thanks for keeping us updated on your recent changes in cables and electronics as you look to optimize the functioning of the CS3.5 EQ. I agree with your suggestion to @Big_Greg to try the Benchmark cables to see if they reduce his concerns about brightness with his Thiel speakers - at least when reproducing music from vinyl - but I would also suggest that he try several other different interconnects and speaker cables as well. My experience has been that Thiel speakers (even my CS2.2s) can be pretty revealing of differences between cables and electronic gear. That's a good thing if you find a good cable match, but a problem if you don't.
For my own listening, I'm trying to find the best balance between high frequency air and detail, midrange fullness and realism, and low end impact without boominess. I'm also trying to achieve excellent imaging while minimizing listening fatigue. I've been generally happy with Cardas cables (like Clear Reflection) that blend the classic Cardas midrange liquidity with the high-end detail of the newer cables in the Cardas line. I don't get concerned when I read about listeners who are looking for uber detail and think that Clear Reflection softens detail too much. Not every listener has the same gear or the same preferences.
I've tried several interconnects (including Vovox Sonorus and Zavfino Fusion) that provide nice high frequency detail and natural tone, as well as seemingly adequate low-end heft, but I've found that over time they just sounded a little too thin and lacking in the richness, fullness, and coherence of the Clear Reflections. I'm not suggesting that everyone should use the cables I use, but I am suggesting that everyone should at least demo a range of cables to see what sounds best with their gear and their preferences. Thiel speakers are revealing enough to show off cable differences, so Thiel owners already have that going for them.