Swapping Platters on Thorens 124

Are you having a problem with the London Decca cartridge and the TD-124 iron platter, or are you anticipating a problem?

I ask because I am using a London Decca Super Gold with my TD-124 Mk I and it works fine.  I am also using several SPU cartridges without any problems.  But if you ARE experiencing a problem I can offer a couple of suggestions:

1- before you replace the platter, try replacing the Thorens rubber mat.  There are several drop-in replacements that will allow you to retain the aluminum outer platter shell.  If you want/need a thicker mat you can remove the platter shell and fit a cork/delrin/leather/copper "mat."

2- If you want to replace the platter I suggest that you use something other than the Mk II aluminum platter.  I am not a fan for various reasons; basically IMO it does not sound as good as other alternatives.  You will be better served by a stainless steel or brass replacement platter.  I know that they are more expensive (but not that much more expensive).  Welcome to the joys of mid-century idler wheel ownership.

Anticipating. I haven't wanted to try it because I don't want to risk damaging the Decca. I also use a Herbie's mat with mine and it's super thin. I was able to grab a non magnetic platter for cheap so I thought I'd give it a try before I invested in a new aftermarket one. 

What mat do you recommend that could block the magnetism if I want to keep the aluminum top platter?

Thanks for responding!

I have been told (by Art Dudley) it is the sub-platter on the Mk.1 that is ferrous, not the top platter. True or false?