Hey, if you want some help with packing mod files to reduce the unpacked size and to get rid of unnecessary files, you can use my Dreamy GRO application. I just released an update for it that supports mods and all kinds of files (even DLL). I have a short wiki page for it as well, if you have questions about it, or you can just ask me.
But I must warn you that it’s not perfect and might miss some files in specific circumstances, so I recommend testing new updates on clean game installations before releasing them.