What about biwiring with silver for High frequencies and copper for low frequencies ?
I do this with AudioQuest KE-4 (15 AWG pure solid silver) up top and Mont Blanc (12 AWG solid copper) on bottom. Used to use this in my main rig, and now brought it back in my 2nd rig. Always liked this combo (going back 15 years), and still like it now. Have compared it to many other AQ models - symmetric double bi-wire, internal biwire, single wire. There’s 2 cable configurations I’ve liked better (both much more expensive), but I like this combo better than all the rest. The AQ hybrids - with copper & silver in one cable - are quite good, but no more effective that this mixed biwire, IMO.
The knock against this approach would be a sacrifice of "coherence" from the asymmetric biwire - but I don’t hear ANY issues with coherence here. Silver helps bring out detail and sparkle. Copper keeps a nice overall warmth. And it all blends nicely. Speaking of coherence worries, my Tannoys pair a metal dome with a large paper cone - and they’re still incredibly coherent, to my ears!