I took a 1" by 3" board about 3 feet long and covered it with speaker 'carpet' ... it works fine, but I may try the door stop ...
wood is too bulky and heavy......when tightened they start to contour to the shape of the round tier making a nice fit...
these door stops cost .78 cents each...when I get time I'll spray them black also. And rubber has a tacky texture to prevent sliding also.