I love tools. Here are some photos showing how I made a pot cushion and grip for my Giffin Grip (a tool used for holding the pot on center for trimming the bottom when the pot is leatherhard).
I just used the non-skid stuff you put under a carpet. The photos pretty much tell the story themselves. Draw circle as big as you would like the grabber to be. (I should have made mine bigger).
Mark cutting areas. Make sure they are a little wider than the sliders.
And there you go. I was often putting stuff down like clay or batting or something to protect the rim and this gives the pots a little protection and holds them in place better.