Help - Cable for High End System - M7s and Block Audio Mono A

My friend is putting together a system and I offered to help him, but at this stage, the budget has grown far above the price points where I have knowledge of components and pairings - I could use some advice.  At this time, we are focused on neutral speaker cables.  These don't have to be end game but enough to get him listening for a long time and not limit the other components.  The speakers are the Magico M7 and the amps are the Block Audio Mono A 200.

Any suggestions in the $5000 to $12000 range for a pair of speaker cables.  The other limitations are that the cables should be flexible (not overly stiff) and not have large modules or boxes in the cable.  Thank you.