The Facnor LX series is advertised to furl easily, even with high halyard tension. Sounds like an issue with the furler, not the halyard tension. Having the sail 'bag' between the feeder and the lower shackle is a sign of little or no luff tension. When I tension my jib halyard, I always check that that 'free' piece of luff comes taut, and then give it a bit more.