[So effectively, you're just reducing the jib sheet pile on your tramp by 3' then, right?
No. You don't reduce the amount of line on the tramp. Basically, you half the amount of line right where the pig tail is. Whatever the length of the pigtail is, that's the amount of line you reduce and that's where it is reduced. The amount of line on the tramp is the same, the amount of line you have to pull through the blocks during a tack is exactly the same. So you really just eliminate about 2 feet of static line from the boat. It ain't much, but it's still something, so that's why racers do it.