I am hanging a pole (made of pvc) on a wall. On the pole will be a roll of kraft paper. I would like to hook up a simple belt driven reversible motor for the purpose of turning the roll to let the paper down then wind it back up. How do I determine the amount of torque the motor should have to perform the task? Please be gentle - I googled the random question to get my registration to pass - I have no clue about the science of these things - normally, if they weren't so dad gum expensive, I'd just buy one of each motor and try them til i found one that worked.