I can't speak to specific tensions, but I can relate the process my neighbor went through with his furling main. His was a C350, but I think the furling mechanism is identical to yours. He struggled the first season he owned the boat to furl and unfurl the main. The next season, he hired a rigger to troubleshoot the system, twice. Each time, they tweaked everything and said it seemed fine, but then, the owner couldn't get the sail to unfurl or furl. I offered to help him, and we were finally able to get the sail to furl and unfurl to his satisfaction. I had noticed that the furling line was lying slack and unsecured, and the sail was sagging and bunched up inside the mast. It was a struggle to unfurl the sail at first, but running it in and out a few times, and moving the boom up a few degrees seemed to solve his issues. I stressed that the tension on the furling line was critical, and must be maintained. A week later, I walked past the boat and noticed that the furling line was slack and the sail was bunched up in the mast. Oh, well.
