I've use a LessLoss DFPC Original into my DAC/Pre to great effect. I've compared it with several much higher priced cords without seeing any improvement. The new C-Marc cords are supposed to be better than even the DFPC Reference while having a lower price point. My impression of Louis at LessLoss is he takes a no-guff approach and I think if he says the C-Marc wire is better in all parameters then I believe him.
..I've got 4 Lessloss PCs that I run and couldn't disagree more. I too have compared them to cables costing considerably more and the held their own. Every one has been purchased used for an average cost of about $300 and even though they are a weird, wrong, and an alternate reality, I have no plans to "upgrade"..
I suggest not being obsessed with using the same brand on all components. Shunyata, Clarity Cable, Ansuz, Lessloss C-marc, and the new power cord from Sraightwire may all work extremely well on your DarTZeel amp.
The Siltech Ruby Hill may be a make or break cord, meaning it may sound great with bloom, smoothness, and power, or it may sound not right at all; too bright and forward, distant bass, and off tone.
For interconnects, I would definitely stick with the best copper ones on the market.