I tend to like the sound of multiple, individually insulated solid core wires for SCs. Harmonic Technology cables can sound great (IMO) and can be purchased used at a reasonable cost for what they are - multiple strands of small gauge solid core OCC copper in foamed PE insulation. You might also look at Morrow Audio that sells cables that seem to be made from many strands of very fine gauge magnet wire, in which each wire is isolated from the other by a coating (enamel typ). Cardas cables are similar, but they also use golden ratio type geometry. I had a pair of Cardas Golden Cross that I thought sounded great in my system and were my favorite out of several types of Cardas SCs I owned.
The Cable Company could be a good place to start if they still do the lending library thing. At least you could try several cables and decide if you even hear a difference and, how big a difference and, if so, which you like best.