I'm a Dummy, Tell Me About Turntable Mats

That is why the Origin Live Mat works so well. This is an engineered material with different characteristics at the record/mat than mat/platter. The goals are to avoid reflecting vibration back up into the LP, to absorb/dissipate them in the material, and to do all this uniformly across the full range of frequency and dynamics. Simply felt or rubber mats just aren't up to the task. The best they can do is make a few areas better at the cost of making some other areas worse. In other words like Ralph says they will not be neutral.

It’s called stylus jitter. https://youtu.be/F65mODzn4Gk?t=778Yes the problem is endemic. Yes it varies all over the place just like you said. I just bought a SG200 so hopefully will hear all the wonderful benefits PL talks about here.

They are all different. They all affect the sound, but in rather different ways. In addition to whatever they do in terms of vibration effects they also add thickness and change VTA and so will change the sound that way unless you correct VTA. 

Because they are all different and because all platters and tables are different it is very hard to predict what mat will work on your table unless someone else with the same table has used it, and even then you need to know what it did and not just that it was "better". So good luck.

The one mat I would pay money for is Origin Live. All Mark Bakers stuff that I have tried is excellent. The mat is thin, only about 1mm and deceptively sophisticated in material and construction. Most mats are just one material, felt or whatever, all the way through. This is a simplistic view of vibration control at best. What you want is something firm but not super hard at the surface, because otherwise anything soft will suck a bit of dynamics. But not too hard or it reflects them back. Ideally vibrations from the record flow through the mat into the platter and not back into the record. This is the goal. Equally important is this happen uniformly regardless of frequency. Most mats (most materials period) absorb or reflect different frequencies differently. This inevitably leads to tonal imbalances that distort the natural timbre of instruments. In other words they sound tilted up, or damped, or in some way have a signature of their own. You don't want this. But you get it with most mats.

So those are the basics. You have a good table. I would get a Origin Live Cartridge Enabler before would mess around with a mat. Cheaper and guaranteed to be impressively effective. Or both at once. Or both and the belt. Belt compliance has a similar effect on tone and dynamics. But that is just me. Good luck!