I've cable tied a 1" block to the outer end of a spreader, run a light line through it (so I'm not tempted to hang something heavy on it) down to a shroud mounted cleat, below boom level to clear the sail. I think I will change the cleat for, or add, a block so the line does'nt fly away when I let it go. I then whipped one end of the line to the other, 6" from the end. The other end is then whipped to the line leaving a 'hole' in, the now continuous loop, through which, you can put the toggle of the flag support rope. Tie the other end off below-job done! You could even whip a loop of bungy cord to the line for the botton flag fixing to keep the edge stretched.