The solution I landed on in the end was using the Kenyon Gyro Stabilizers on a simple shoulder rig, two of them, one for each axis. And I find it brought a lot, I had almost no visible vibrations from the helicopter. But still I had very unstable material, the Gyro’s are not enough for taking away that, then I think a Movi, Ghost or similar rig could be recommendable, without having tried it. What saved me was the Adobe Premiere Stabilizer, even if I had to crop a lot on some clips it gave me a totally different movie.
Lens was a Sigma 35mm on the 7d, but I often I wished I could go a bit closer without having to ask the pilot. In general I noticed that the closer I was to the ground the better the shots got since the movement is more visible, of course depending on what you are looking for.
And wear gloves, I forgot and at some point couldn’t feel my fingers anymore…