How to reduce the offset

Hi,

I need an amplifier, differential in, differential out, three ranges 80V, 8V and 2V, common mode range of +-400V, 400M Input Impedanz. I found an solution, but the Offset is very high expecially in the 2V range. How can I fix that?

I built 4 boards, the Offsets are very different, no idea why.

Here the results.

I am not sure which op-amp is good for the servo stage.

I also need a very high capacitor to stop oscillations of the servo loop, here I need also some help.

Here my schematics:

Thanks for helping out.

With best regards

Gerhard