Be sure the paper is tightly fitted around the rolling pin, and tape the ends of the paper down. Now your rolling pin is covered and only the paper will get paint on it and you can simply remove the paper to have your rolling pin back.
The best way to cut the rubber stamp sheet is with a long ruler and a rotary cutter. This ensures a clean cut and straight lines.
Determine what size and style of stripe you want, and cut the rubber sheet to that thickness.