PTFE mat, anyone use it?

[ErnieV]

Hello people
I have used the recommended PTFE and cardboard seal in the past.

However, when doing a search on eBay recently for clamps, I discovered that they come with a PTFE gasket.

So, I decided to try a search for PTFE mat so that I can make my own. There was plenty available.

Anyone used it? What thickness do you recommend?

Regards
ErnieV