It's not very long after the solstice, though, so the daylight hours are still too long. If I were you I'd simply put them inside under a fluorescent on a cheap kitchen timer for the 3 days, or if you have to, just put them in the closet. It's not going to die in three days, but if you leave it outside they're not going to completely revegg or anything, but the off and on schedule will stress the hell out of them. They might be tempted to hermie. You're better off bringing inside. Beautiful plant by the way. Good job, dude