I wouldn’t count the Moonstone as a low-compliance cartridge. It’s made in Japan, and thus spec’d at 100Hz rather than 10Hz (Euro). Its compliance is really more akin to 18 - 22 (@ 10Hz), which is into high-medium compliance territory. I certainly wouldn’t go out of my way adding a massy headshell here.
Also in general - it’s unlikely any MM cartridge would have compliance as low as 12 @ 10Hz. It’s MC cartidges that have a much stiffer suspension and robust damper because of how they work.