I have sought a solution that is easy. First, I have the envelopes looked through. This "rubber" is like like nothing. In the beginning I had the rubber in several positions to try, until I found a great position for me.
The rubber feels great, not to be compared with a Einmachglasgummi. It is very pleasant on the skin, something like a cloth-like not handle conventional rubber. And of course, easy to use :-)
I would highly recommend this handle very. I use the Kindle for the Paperwhite.