Mine is just a snap hook on about a foot of cable (pigtail), clamped to the backstay.
Have read of a masthead topping lift, but it's an illegal modification if you're interested in class racing (or later selling the boat to someone who is). The details are simple though:
"A line from the masthead crane down to a block on the back of the boom then to a v-cleat on the bottom of the boom. This allows to the boom to be raised by just by pulling the line. You can drop the sail simply by tensioning the topping lift line. No need to hook the boom to the pigtail. It also allows you to raise the boom a little in light winds so the weight of the boom won’t pull the leach too tight."
Expo Solar Sailer