based on the measurements of the buckle (4.5") the squares should be 3/4", also only the horizontals are quilted, the verticals are very small pintucks on the top layer only (done before quilting).
Fabric wise, the current theory is that it's a black silk, and the thread is like a dark tan/gold colour
For more info, you can check my post on the Knights of Ren FB page:
https://www.facebook.com/groups/Kni...3/?match=cGF1bCByb2JpbnNvbixyb2JpbnNvbixwYXVs
That test I did was done from publicly available references (the vanity fair shoot and the battlefront 2 promo shots) and I was fairly confident about it, but I just today got shown a close up picture of the real deal (can't be shared though) and I'm 100% confident in it now, the only thing I'd change is the fabrics I used (ie. silk and tan thread).
Also, don't forget the detail on the shoulders.
http://i.imgur.com/F45imB8.png