Not quite a breakthrough. But I have noticed at particular times, especially when watching TV or using my computer at mid-distance, that my diplopia is no longer annoying. Also, my eyes look straighter than ever, and I'm seeing significantly more depth in VR games. I'm not sure what the difference is. I suspect that it's just time, continuous mindfulness about using binocular posture, and using VR to provide a hyper-binocular stimulus.
Haven't been doing Brock string or anything like that. Just VR, and trying as much as possible to be aware of the use of both eyes. I'm also careful to use both eyes when reading, using the reading technique prescribed in previous entries.
It's getting easier and easier to internally conceptualize what it's like to use both eyes. Holy crap, VR beginning to get intense as I lose the suppression.
I'm more confident than ever that I'm going to achieve my goals if I keep going.