Speaker Cable, matching to Harbeth 40.2

I've used 12 gage Duelund on my 40.1's and 40.2 Anni's and have no desire to change.  I've owned considerably more expensive cable (up to $3.5K) and prefer the Duelunds.

I've used 12 gage Duelund ...

I like Phineas.

Cardas Clear Cygnus

Call the cable company..they keep database on good synergy 

Wireworld Mini Eclipse?

I have the HARBETH 30.2XD’s which have the same drivers as the 40.x series.

do cables matter for peak performance? You betcha.
I experimented with numerous spectrum options and found that CARDAS CLEAR or CARDAS CLEAR REFLECTION operated as best of breed in my system

They bested the CHORD Odyssey, NORDOST FREY , VAN DEN HULL, and a bevy of other pretenders my system. .The CARDAS models smoked all the MOGAMI, CANARE, and BELDEN budget choices.

Try combax harmonix you will be shocked by its musicality