[Chak]

I've been told that some teams use slicker bumper cloth to assist in escaping pins, but doesn't the bumper number material also change the coefficient of friction of the bumper? What is the best bumper number material/method to complement slicker bumpers?
On the other hand, what is the best bumper number material/method to complement rougher bumpers?

To start, one of our mentors speculated that sewn on numbers might be rougher because of the seams.