I've decided it's time to introduce Willow to the double bridle. The canter is lagging behind somewhat, but she's schooling solid second and even a little third in walk and trot, so why not. I'll just ride in it once a week for awhile. (I'm a big believer in schooling in the snaffle most of the time for as long as possible. I think there are often some major training elements missing if a horse requires a double to be rideable. Your mileage my vary.)
I rode schoolmaster Aron in the double every so often, but that bridle was already fit to him. I've never fitted a double to a horse from scratch before. There's a lot to consider! Between all the various components, the possibilities are nearly endless. And expensive! Luckily, it turns out the trainers at my barn have a whole drawer full of bridoons and curb bits in several sizes, so at least I'll be able to try various combinations without spending a lot of money.
I hope my fingers remember how to manage all those reins.