Optimizing Movie Render queue EXR file export sizes

Hi All,

I’m exporting a few varieties of 4k exr files from the movie render queue to send to nuke for compositing.

I have been mixing and matching multiple render passes packed in to try and find the most optimized exports; AO, worldspace normals, world position, motion vector, world depth, ZDepth, cryptomattes (separate passes for full and material), etc.

There is an example file in the documentation and it is CONSIDERABLY smaller than my exports! Even considering mine are 4k and theirs is 2k Render Passes | Unreal Engine Documentation

Does anyone know of any optimization techniques to reduce exr file sizes out of unreal?