Sony A7/S/R mark II full spectrum internal light leak correction

Hi!

What process would you recommend for processing images taken with second generation Sony A7 cameras?
Their problem is that there is an internal light leak, due to an infrared LED in the shutter, moreover, the sensor moves slightly due to the internal stabilization mechanism making the dark less effective.
Using "Adaptive data pedestal" the result should improve significantly but as you can see from the attached image, the stacking output is pretty awful ...

Sony A7RII, 680x30", ISO 3200 (300 flipped 180°)

240 darks, 20 flats

Settings used:

2)

 Everything else set to "automatic"

4)

 5)

6)

I think I can't do better to fight gradients but I'm probably wrong...

Here is a single dark, unstretched:

You can clearly see the patterns in the final image.

Is the adaptive data pedestal performing bad with this kind of data?

I thought that flipping the sensor 180° would help APP to determine a better normalisation map, but in fact I just destroyed both sides of the picture doing this...

I finally arrived to a "good" image with this data but you'll imagine how much work it represented:

Thanks in advance!