Turntable Mats: Rubber, Felt or Cork.

@atmasphere You are correct regarding the damping ability of vinyl due to its light weight.  When I was experimenting per my post above, I recall leaving the rubber mat on the platter which effectively damped the ringing of the metal platter, then using a vinyl LP between the mat and LP I was playing after adjusting the tonearm height slightly.

Herbies sells these rubber dots, 2" in diameter and a thickness of maybe 3 or 4 sheets of paper (so very thin), and seems to be made out of cloth impregnated neoprene that has very effective damping characteristics.  I suggested he make a turntable mat out of this stuff but never heard back.  I thought it might work well on my Linn in place of the felt mat.

The TTW mat had some sort of massy metal base with a delrin top surface.

I fail to see how another lp ( or similar) product could be as effective as MyMat. It would require that at the very least the lp/mat and the lp playing be perfectly flat. That's hardly possible on a consistent basis. This is the first hurdle.

If you haven't yet read one of my customers' posts in Member's Reviews, do so. He used/uses a KAB polyglass mat and describes his experience with MyMats.

1) I can't find the MyMat on US Audio Mart. A little help, please?
2) isn't it the height of insanity (or arrogance) to recommend that one spend $250 on a mat for a Linn Basik? That money surely could be better spent.
3) I have a Linn Basik in my "B" system. It came with the original felt mat which causer more ststic than anyting I ever used before. I tried a few different leather, cork and rubber mats and settled on a 'Simple Mat' similar to this one.
https://www.amazon.com/dp/B07G716NPQ?tag=duckduckgo-d-20&linkCode=osi&th=1&psc=1
It sounded better than the felt and it didn't stick to the LP every time I changed records.
4) In my main system I have an Oracle Alexandria MK III. It came with a felt mat that was soft on one side and harder on the other. I replaced it with a sorbothane Groove Isolater that I had from an older Alexandria; but by that time Oracle was recommending an acrylic mat, which they sold for $215 in 2016. I thought I'd try an inexpensive version I got on ebay before I committed that much. I liked it so much I got one for the Basik, as well. Now I use one on the Alex and simply add a Wasabi (Highly recommended as @cardani mentioned) when I'm playing an LP under 180 grams, so I don't have to adjust VTA every time.
On The Basik I use an acrylic mat with the Simple Mat to soften things up a bit, as it fits that system's sound better.

5) The Basik does not have a very powerful motor. Don't use anything too heavy and Linn does NOT recommend clamps or weights for this reason.

Best of listening, and I am interested in your mat, @slaw, if I can find it

1) I can’t find the MyMat on US Audio Mart. A little help, please?

@2channel8
You’d better look HERE at the product Slaw is selling even after his listing has been removed. Does it looks like something anyone would buy even for $49 ? Up to you. I think soon we will see someone selling just a piece of paper for $50 claiming it's the best solution ever made. 

2) isn’t it the height of insanity (or arrogance) to recommend that one spend $250 on a mat for a Linn Basik? That money surely could be better spent.

Linn Basik is an awful turntable, but Sakura Systems THE MAT is an excellent mat for $250 even for turntable that cost 20 times as much. Its predecessor Boston Audio Mat has been reviewed worldwide, actually with rave reviews. And it’s not a funny looking DIY product (badly cut with scissors) like the one above, it’s a serial product sold and shipped worldwide to many audiophiles. Ain’t cheap like almost everything in high-end. Manufacturing tour is here.

Read reviews if you want to know more Boston Audio Mat (latest official version is The Mat aka BA mk3):

http://www.6moons.com/audioreviews/bostonaudio/mat.html

http://www.enjoythemusic.com/magazine/equipment/0205/bostonaudio.htm

https://www.theanalogdept.com/bamat2.htm

http://www.soundstagenetwork.com/vinyl/vinyl20080515.htm