Francesca Knowles wrote:
If it's not too complicated to take the roller off, I'd do that and hand roll the fabric back on. Then reinstall and the first time you pull it down it will become tensioned again.
That won't work correctly as it still has some tension on it when closed. As for the proper tension I believe the best thing to do now is using the vise grips remove the tension on the other end and keep count of the number of turns. That way when you rewind it you can get the same number of turns on each end which is important so it will close evenly. Just take your time and be careful as they can hurt you.