Some great advice thus far. I’d add that buy used because if you don’t achieve what you seek, you can sell them for what you paid. If you buy new, support your local dealer and try them in your system to know 1st hand if it’s the right combo.
The cables I’ve liked the best are OCC wire to start with. Ocellia are sublime, and should put you in the right place. If by chance you’re running Sylvania 6SN7 in the MW LS100, get them out in favour of a different tube like some 40, or 50’s RCA. (I had a LS100)