I use a Black & Decker RTX rotary tool set to the lowest speed, about 12,000 rpm, with a small cup hook in the business end. On the furling board I have marked off the 10% line and simply stand over the board and cease the spinning when the 10% mark is reached. That done on both legs, they are then reverse spun for the final furl using an old power drill (the RTX has no reverse polarity - the only drawback to an otherwise perfect furling tool).

Then Shorb loops in both ends and a vigorous freehand whirling to take all the residual torque out of the material.