jxo, I did not use any of the 3dr solo gimbal. I used the go pro fixed mount that came with the solo and removed the center leg. My mount is attached directly to the plate.
My mount is something a radio controlled modeller gave me, it is basically 2 brackets, I have mounted a servo and a couple of gears on it (one on the servo and one on the mount) to get the camera side of the mount to tilt.
I used an old analogue servo I had in my parts bin and added a 3.3k resistor to each side of the servo pot to give me more travel ( I get approx 75 degree movement)
I solder a wire to the RC6 pad of the main board and this uses the paddle on the controller to operate the servo to tilt. I had to make a change in the Mission Planner software, setting RC6 from 0 to 1.
The camera is using the time-lapse function) intervalometer to take an image ever 15 seconds. I am looking at setting up a shutter trigger but will need to go to open Solo 3.0 operating software, my solo software is stock.
Thats about it, here is a closer pic of the actual mount with camera, hope this helps. It is by no means the perfect solution and I am not an engineer but it works for what I want to achieve, it has evolved from the fixed mount I started with, see here
Camera Mount - Lumix TZ110
I hope this helps, cheers, Rob