So, I've managed to fix the "MCRN Scirocco (Test)" mod authored originally by user: Lord_set, found on Mod.io here: https://mod.io/g/sins2/m/mcrn-scirocco-test

I've updated the mod for compatibility-version-2, the game loads it and runs it just fine.  However there is 1 error thrown during loading for each mesh file the mod comes with, skipping the errors works and after loading there are no more errors thrown.  

Error given for each mesh file (i've redacted the exact path from my PC): 

Error reading [(redacted_path)\meshes\mcrn_cruiser_scirocco.mesh] : Not enough bytes read. expected=1 actual=0

Is there any information on authoring mesh files that I missed somewhere?  ideally .gltf to .mesh conversion, and somehow to open or edit existing mesh files?