Since your SET has quality output transformers, I'd expect that you don't need to overcome any high-end rolloff by using silver cables.
I use the all-copper Sonoran Plateau cables in my system with a SET amp, and feel very happy with them.
I work for Starsound, but I don't have to personally use any of their stuff if I don't want to. The Sonoran cables sounded just right in my system, after trying several different kinds, including DIY stuff. They had a very good neutral sound, and the price was in a range I could afford.
I use the all-copper Sonoran Plateau cables in my system with a SET amp, and feel very happy with them.
I work for Starsound, but I don't have to personally use any of their stuff if I don't want to. The Sonoran cables sounded just right in my system, after trying several different kinds, including DIY stuff. They had a very good neutral sound, and the price was in a range I could afford.