Solid core OFC vs stranded OCC copper

Solid core speaker cables definitely sound better than stranded. Tara Labs and Audioquest both make excellent solid core cables. Audioquest Rocket 88 is one of my favorites. 

Occ. period, 

I prefer solid core OCC/OFC over stranded after testing a few brands and set ups.

For some reason it performed better in my small modest system.  I've tried Silver Sonic, higher end Audioquest, and lower end Kimber Cables.  The best was actually "Anti-Cables" done in true bi-wire. 

This will sound ridiculous, but I see one advantage to stiff solid core is that the cables suspend in free air on their own....no need for cable risers!!!

It might be worth simply testing really good solid core for a week or so and see how you like it.  It seems a lot of folks who use it, swear and stick with it. 

Well, if we're discussing sound qualities, a little this, a little that, I use combos of everything and various metals as well. I'd say vast majority of what I have in entire system is litz.

You should go all solid core, you would get better  improvement than optimizing your network.