After some experimentation, I found only one combination that works, but I'd still like to know why.
Shooting with Nikon D70s, Small File Size, Low quality, 6 Fisheyes, stitched and rendered in Realviz Stitcher with minimal compression; final size 3300 x 1650; this file does not grow, in fact it goes from 800KB to 723KB as a JPE.
When using large image size my final rendering is after DXO processing is about 800KB and grows to over 1MB.
I know that the content of the image can cause the size to vary, but this seems to be more of an issue of the original resolution of how the shot was taken. Any other opinions, getting tired of this trial and error.
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