Nfk,
There are posts and reviews posted around the internet with the thickness etc. You can also tell by looking at the finished product at the edges of they are not blended well after they are shaped and cut. At first most people were using .060 including some of the big names, and you can find reports of them breaking belt loops or cracking at the rivets due to the hole in the ktdex weakening it significantly if placed to close together. .060 is easier to work with but makes for a less than desirable holster if you want it to last. .080 and .093 is recommended for gun holsters and .125 is the recommended standard for belt loops but not many people us the correct material. The reason .060 is used so commonly is that it was used to make knife sheaths for a number of years since they carry less weight the application was right for it. The weight of handguns however dictate a better product. I have experimented heavily with many grades and types of kydex, by requesting the samples available on kydexs own website and speaking to their reps to find the best material and through speaking to them is how I found out what materials companies have been buying in bulk.
joe