Good stuff, the technology is really improving hey. I liked the tip of turning off GPS mode to stop yaw waggles if you've got a 2D gimbal. How is the latency with your lightbridge setup?
I've been setting up a Hexa with 2D gimbal recently, lots of fun but doing it all yourself is definitely the slow path to good video. Have you considered propwash as being part of the problem with jello on your old rig? I had similar issues until I spread the front two arms out a bit. I'm starting to think that I need to move the camera forwards and up a bit, to put it pretty much between the front two props, to help with this issue as well. It would also eliminate the issue of sun shining through props (although a cheap hood over the lens can also help with this issue).
So many options, so much tinkering required.
Re propwash - its a possibility.
Lightbridge has about 1/4 second latency - which is pretty damn good - in fact i would say DJI have the trump card up their sleeve when it comes to that technology.
The review is very positive - DJI have included so much value and functionality in that package.
For me multi rotors were a way to get a camera airborne (i have flown plenty of aerobatic electric rc planes to scratch the high performance itch).