Try doubling it up and see for yourself. That's the only way to know.
I found the Duelund wire fairly overrated, and in my personal opinion, it wouldn't be a desirable match for the Harbeth 40.1. I find that Harbeths, with their mid-centric BBC sound signature, often benefit from a good silver interconnect and SS electronics. The Duelund is kind of a warmer, muddier sounding cable which probably isn't the right direction to tweak those Harbeths unless you're dealing with a fairly bright or edgy source chain.
I found the Duelund wire fairly overrated, and in my personal opinion, it wouldn't be a desirable match for the Harbeth 40.1. I find that Harbeths, with their mid-centric BBC sound signature, often benefit from a good silver interconnect and SS electronics. The Duelund is kind of a warmer, muddier sounding cable which probably isn't the right direction to tweak those Harbeths unless you're dealing with a fairly bright or edgy source chain.