Has anybody tried using single solid core cables?

At a recent hi-fi show an exhibitor auditioning $47K speakers repeatedly asserted the following: "Any solid core wire, even $0.03 a foot is better than any multi-strand available. Experiment for yourselves, you will be amazed."

My question before I ditch my multi-stranded Audioquest Indigo cables in favor of 4 individual single solid core 18 gauge cobber cables from Home Depot for my newly acquired SA Mantra 50s, has anyone tried using single solid core wires?
On the house wiring, #14 gauge. I'm an electrician and I was surprised to find that Audioquest Type 4 solid core cables are much stiffer and stronger yet not brittle as you would expect. The type 4 has 4 conductors, 2 17 gauge and 2 20 gauge. Whatever Audioquest is doing to the copper seems to work, they are much superior to the stranded copper #12 they replaced in my system.
My entire system is solid core AQ stuff, and it works as advertised. Some things in cable theory make sense, and others not so much (to my addled brain anyway), and spiraled solid core done well does make sense as a noise reduction idea. Anti cables work well for some people, but the fragility of the merely painted bare wire seems dangerous territory so my rig looks like it's being attacked by bungee cords...and that's fine with me.

I like AQ a lot and am thinking of getting another pair for my Thiel 2.7's Which ones are you using? I have had the Rocket 33 and Rocket 88's with DBS. Thinking of getting another pair of 33's.
After many years of trying every brand and geometry of cable within reason. I have always found myself settling with solidcore cables. Generally they always seemed to sound more focused and direct sonically.

I like the AQ DBS cables I have tried, but they seem to focus more on treble extension and speed. I just find they don't do timbre and 3D depth so well when compared to others. A little solidstate sounding if you know what I mean?

I too have ended up with DNM after many exotic cables (analysis plus golden oval/AQ WBY/ Virtual dynamics Genisis/Kimber Black pearl/ etc) Although I do like MIT cables very much for their 3D depth.