The Gunze color is pretty solid...I'd have used it but the heat here is causing paints to dust like nobody's business, and I've been having the best luck with enamels, so MM enamel Middle Stone was what I went with. Overall, I'm happy with it.
If you're willing to order, I believe Vallejo and/or Lifecolor have Middle Stone. The Vallejo Model Color line tends to be a bit suspect in color accuracy, but the Model Air line is very good in that regard, and every Lifecolor paint I've touched (all five of them!) has been about as dead a ringer as I could hope for.