Removable headshells

I don't think that you need to be concerned at all. Primary resonance of the moving system is easy to measure so it gets a lot of play. But it is below the audible range so is related to tracking, particularly over warps. I would use a lightish headshell and be done with it.

What really screws up sound quality is the secondary, bell like, resonances of the moving system, which, most definitely, fall within the audible range, and have a much bigger impact on sound quality. Hard for the amateur sleuth, or scientist, to measure.

My greater concern would be the total weight of the tonearm and cartridge and how that will interact with the Linn suspension. Good luck and YMMV.

A heavy headshell ("too much weight") can be your friend if you want to use a low compliance cartridge and need to increase tonearm effective mass.  One very good one that I use with a Koetsu Urushi is the Ortofon LH9000, which weighs 18g, as compared to most of my other headshells that weigh 9 to 12g. I mounted it on my FR64S tonearm, which is already a high mass tonearm, but the FR headshells are not so great sounding. With the LH9000, the Urushi never sounded better.

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.

If you don't want to accept what I said, trust mulveling on this one.  A heavier than necessary headshell would be deleterious in this application.  

I use the head shells made by Pete Riggle of VTAF and Woody tonearm fame. The headshells are made of wood, and only 6 grams. He also provides a 5 gram brass weight for when it needs to be heavier. Also, I love the finger lift he designed. Real easy to use. 

David