SP10mk2: OMA Graphite plinth vs.Dobbins plinth

According to the price lists they are in one category, but anyone could comment on quality/performance? At the moment i use big Teak Wood plinth (just $750) custom made in Taiwan for my SP10mk2. Looking for upgrade in the future. I use my sp10mk2 with Reed "12 tonearm now. Doest the plinth actually makes a big difference in sound? My stand is well damped with glass, metal and sarbothane in between.

1) Oswald Mill Audio graphite slate plinth (single layer) $2750, double layer looks fantastic but cost $3500

2) Steve Dobbins famous custom plinth cost $2650 including three Stillpoints feet and automotive show quality paint in black or white. Design has changed many times, still hard to find any current plinth picture online.

I know there are Albert Porter's and Artisan Fidelity quality plinth available, but i don't like the design (i mean just how it looks) for SP10.
chakster, do you, or others here, have any experience with the AT-666 mat?  It was designed to add vacuum hold down but I recall reading of some using it just as a replacement mat.  Raul in fact recommended it with the Technics SP series as a mat only.  It weighs 1.4 kg.  Also may be easier to find than the CU mats and for much less money.

With some of these heavier mats I'd be concerned not only with start-up torque but possible excessive bearing wear.

I am sure that there will certainly be greater wear on the thrust pad, adding weight not calculated in the design phase by the engineers who developed the SP 10.
Fortunately, it is available as a compatible replacement part
How did you clean your cu-180 without removing the varnish/laquer.

btw - I have a Tenuto copper mat here at the moment. I am borrowing a friends while he borrows my SAEC SS300
I used a common copper cleaning product and an old toothbrush because the mat is not exactly smooth but has micro grooves like vinyls
I insisted a lot and performed more passes but in the end the result was excellent.

After polishing, with a spray I gave a couple of light shredded transparent varnish.

For me the Tenuto mat is a good product, well done, with a weight very similar to the MS CU 180 and reasonable cost.

I was thinking in the future to buy one for other SP 10s I own.

What about the size Tenuto?
Micro Seiki fits in (for Technics SP10mkII platter) like it was made for it, not like other mats which can be smaller or bigger in diameter. Micro Seiki is the best for Technics owners. The CU-500 is much thicker than CU-180

Here is my CU-500: