Jamie,

Double ratchets work, at least that is what my own 56 kg, 1.62 mtr female crew says. (124 lbs, 5 ft 4'). You just have to remember to relax your muscles ones the spi sheet is pulled tight. At first my crew held the line with the same tension as when sheeting it in, then the ratchets obviously don't help as you are still holding all the force by your muscles. But ones you learn to relax your muscles you'll find out that it will take only 2 fingers to hold the sheet. The rest is the skippers work. He (or she) just needs to steer, steer and steer to keep the spi on the verge of collapsing. Continiously trimming of the spi is slightly better but if your crew is not up to that then steering is a good second, especially on the Blade which steers very well in my experience.

Wouter