I Just found this: http://jsyang.ca/hacks/gear-vr-rev-eng/
they seem to have a webbluetooth demo running that has access to the entire controller. They even metion what I think is your attempt at one part. They apparently reverse engineered the “driver” from the gear vr apk. Hope this helps, I’m hoping for 2 of these to finish my diy setup! These controllers seem to be the best option for a vive controller clone other than a diy one with arduino.