401 birch or slate?

Looks like I'll have to import a slate plinth from the UK. Not much interest on this side of the pond and PA-based Oswald Mills start at a ludicrous $5000. 

@noromance
From personal experience the SMD Quartz plinths built in the UK are very good. However, since you appear to have a reasonable plinth already, I would suggest you consider doing the following -

• Large platter & bearing from Classic Turntables - this improved the timing and coherence from the 401 substantially.
  
• Idler wheel from Artisan Fidelity - this added a significant level of refinement, particularly in the high end
  
• Power Supply from Classic Turntables - significant increase in resolution and high frequency purity
  

These mods I heard in a system I know well and can highly recommend. They took a fully refurbished and blueprinted 401 to another level by a considerable margin.

Thanks @dover . This is very good stuff. I’ll look into the AF idler wheel for my birthday! Looks like I will go with slate. I have found a source in the US.
Not sure if I should open a new post but...If using slate, should I use an arm-board or mount on the plinth?

I went with slate. See my Virtual Systems entry for update.

@dover  You said "Idler wheel from Artisan Fidelity - this added a significant level of refinement, particularly in the high end"

Could you kindly elaborate in a bit more detail what you mean? I'm tempted to get this wheel. I notice there is another offering from Audiosilente in Italy for 1/4 of the price. Thanks.