Depending on your space limitations and available materials I would use a broom handle through the center of the roll, take a piece of wood and using finger clamps clamp it to a table (think yardstick size) slip the paper under the clamped piece and pull off and cut along the straight edge to whatever size you need. Especially if you have a rolling cutter like the ones used for quilting. Those stay sharp for a long time and cut very easily. Won't be the fastest way to do it but you'll be able to make clean cuts