Let me offer my limited experience. I own a Moth s45 SET amp that outputs 1.8-6wpc depending on output tube (either 2a3 or 45) rectifier tube and bias point. After reading many posts on the benefits of small gauge solid-core wire, either silver or copper, I decided to try it myself. My existing bi-wire cables were typical Audiophile fare; Silverline Audio copper cables that match the internal wiring in my Silverline speakers.
I substituted 24awg (5n) 99.999% pure silver wire with 20awg teflon tubing, bare-wired to the top-posts, while keeping the Silverlines on the bottom (for now). RESULTS: IMS the performance was much improved, paralleling many of the benefits of SET amplification itself. The cost of $64 for a 10' pair was a plus. Highly recommended. YMMV.
I substituted 24awg (5n) 99.999% pure silver wire with 20awg teflon tubing, bare-wired to the top-posts, while keeping the Silverlines on the bottom (for now). RESULTS: IMS the performance was much improved, paralleling many of the benefits of SET amplification itself. The cost of $64 for a 10' pair was a plus. Highly recommended. YMMV.