I saw J0bro's design, but it didn't fit my frame, so I designed a new one which fit my dimensions. I also didn't feel like ordering the vibration dampeners so I designed those as well and printed them in NinjaFlex which seems to have worked. The video from the first flight can be seen at https://www.youtube.com/watch?v=YM12zOrDXgE and you can see very little jello despite propellers which aren't up to the job (I've got stiffer ones on order) and haven't been balanced. I sanded the raised part smooth and installed the clean plate with the thick side up towards the camera - this provides more clearance for the vibration dampeners between the plate and the camera. I used 3 small cable ties in both slots so the plate wouldn't slide back and forth. The clasp of the ties is underneath in the same space as the dampeners.

I printed the clean plate out of PLA with a fairly high infill 90%. I printed the vibration dampeners out of Ninjaflex with only 1 outside/top/bottom layer and 10% infill - it needed to be as squishy as possible. Even 2 layers made it too stiff and hard to install.