Hey I'm not sure if you are still interested in other bridles, but there is also the micklem multibridle. It has 5 settings and can be used as a lunge cavesson, a regular bridle, and 3 different bittless bridles, from mild to strong(a sidepull, a cross under... and I forget the 3rd one...) It also has an interesting design where it is formed around the horse's skull from the inside out where it works to avoid sensitive nerves that apparently make a horse rub his head after workouts. Here's a link: Welcome to William Micklem's Rambo Multibridle
(sorry my first time posting a link on this forum, I'm not sure if that worked)
Another natural thing you could do if you're completely natural and therefore kind of crazy; you could try a cordeo, or neckrope. That is bridless riding as your cues come not just from the cordeo, but your entire body as well using weight shifts, subtle cues, and verbal cues. And a lot of people think you can't do anything without a bit, but that isn't true. If you search bridless riding on youtube(or I can post links), there's this amazing user named Bonvaus(something like that), and his horse Bon Voyage can do tempi-changes bridless! And he's just one example Okay sorry, I totally just wrote a novel, I hope I helped somehow? And I also hope that everything goes well with your girl!