Can't help you, Matt. A common derailleur chain, or even a good one like the KMC X8 that I use on my Rohloff, is made to tolerate a good bit of side to side movement. A single-speed chain doesn't need the side to side movement, so can be more cheaply built. Though a big admirer of KMC higher-end chains, I also wonder what the X1 brings to the party to justify the price. KMC's coy generalities sound like marketing department snake oil.
Andre Jute