Turntable mat Sonic differences; cork vs. leather vs. rubber compound

I know there isn't a precise answer for this question but your feedback would be appreciated. There are a lot of differing TT mats out there, all with pros and cons and I've heard both good and bad about most of them. My question is this...

What are your experiences with leather versus cork verses rubber compound mats? I know much of this is relative to the turntable in question but there have to be some general sonic characteristics specific to each. What's your opinion?

(By the way, I'm running a Rega P3 with a glass platter and white drive belt, RB300 arm with and underslung IsoKinetic counterweight, all supported on 3 Vibracones.)

Basically the harder the mat the harder or more harsh or detail the sound will be. Mass loaded TTs do better with softer materials and spring loaded TTs do best with cork. 
..just buy all that are available for sale, then make your own from anything you can.....it still won't be perfect.....there is only one more to evaluate.....
get rid of the Vibracones.
Morbius again with a follow up on my TT mat issue...

I had been using the 2mm thick felt pad suppied with the Rega but found it sounded flat, ergo the search for a options. So I proceeded accordingly...

1st - I tried an older thin, high density rubber pad in place of the Rega felt but it compressed the top end, made the midrange a bit murky and seemed to reduce the dynamics. So on to phase 2...

2nd - I bought a sheet of 3mm cork, sanded it smooth and cut it to fit the platter. Overall, the sonic signature tightened, the image and the bass more defined but it flattened and deadened the sounded. Moving on from there...

3rd - I cut a 1mm sheet of cork to 11.500" and cut out 4" in the center to accomodate record labels, then bonded eight 1.500" x .750" 1mm cork pads equidistanty spaced around the perifery .750" from the outside edge and six .750" x .750" cork pads from the inner edge of the cork disc and placed it on the glass platter. Sonically speaking, it really open up the top end and exaggurated the airiness and tightened the bass, the vocals became a bit edgy and the image became less deep and more vague. Closer, but no cigar. So...

4th - I cut a thin piece of felt (-1mm) to 11.500" that ran from the spindle to the outside of the platter and placed the new cork mat on top. The background became blacker, image depth returned, surface noise less evident, the vocals were tightly focused and the bass regained its' punch, depth and detail and the frequencies are well balanced and great dynamics. I couldn't be more pleased. So my journey has ended (for now).

(By the way, I swapped the Vibracones for carbon fiber cones and the vocals and bass noticably tightened up. Thanks for the tip.)
Morbius again with a follow up to my last entry as there may be others considering making their own TT mat...

I found there is (not surprisingly) a difference in the sound of different types of sheet cork. The higher the density of the cork in terms of stiffness and hardness the higher the resonanant frequency and sharpness of the playback. This results in higher definition of the upper frequencies and more airiness but at a cost of diminishing the midrange and generating a slightly more brittle nature to the music.

The softer cork material, typically the more flexible cork sheet with larger grain, drew out the mids and deep bass a bit better and softened the top end resulting in a better overall balance across the frequency spectrum.

3rdly, the amount of surface area of the cork seems to reflect the resonance properties of the cork to a greater or lesser extent.

The more I played with this process the more it became evident that the type and quantity of materials used in making a TT mat is like modifying and tuning a stringed musical instrument. There were noticable variations in the sonic personalities of each the half dozen mats I manufactured. All this experimentation leads me to believe that one can significantly tune their TT to suit their personal taste in playback just by making and modifying their mat; without blowing $200 on various retail TT mats to find your musical truth.

...and the best part is... so far all the materials have cost me less than $15.  
@morbius2130aol ,

I was glad to help but more glad that you had the incentive to actually try something else
Carbon fiber would have been the material I’d recommend.
I really appreciate your willingness to try different materials, evaluate, then come to a proper conclusion.
After this you made your conclusion based upon your personal experience!