Well, could you put a "Cunningham cringle" in the foot of the sail near the gooseneck fitting, much as is done for the luffs of mainsails to fit a racing length, or just to get sufficient tension when the luff is too long? It may create a wrinkle in the tack area of the sail when you crank in (forward) on it just as it does when you crank down on a conventional Cunningham, but that should be fairly localized.
You'd have to put some reinforcing into the area of the cringle, but cheaper than recutting the whole sail or buying a longer boom.
So you see I vote with your MacGyver concept (e.g. "how to make a nuclear accelerator from a fountain pen" ;-), except it's MacGyvering the foot, rather than the boom, to be a little shorter by putting a tiny "reef" in it where it would do the least harm.
Whatcha think?
You'd have to put some reinforcing into the area of the cringle, but cheaper than recutting the whole sail or buying a longer boom.
So you see I vote with your MacGyver concept (e.g. "how to make a nuclear accelerator from a fountain pen" ;-), except it's MacGyvering the foot, rather than the boom, to be a little shorter by putting a tiny "reef" in it where it would do the least harm.
Whatcha think?