Hello :)
The video will be done by tomorrow morning, and the final seamless loop tomorrow during the day. There's still some work to be done in post for the final video.
As for the .c4d file, how i've mentioned that i've had to switch technologies in order to achieve the demands, the original simulation was not done in Cinema4D, as originally intended, but Blender. However, the final step in the process is still done in Cinema4D, like the remeshing of the simulation.

Now, to answer your question about conversion:
The initial simulation and animation was done in TurbulenceFD, which was later cached and converted into a .VDB data-set, which is 14GB in size(450 frames of simulation voxel tree raw data). From that point, the .VDB raw data was loaded into Cinema4D R20's new Volume Loader, and meshed with the Volume Mesher generator. After that, the entire meshed simulation was baked in .ABC file (Alembic), since Collada doesn't support animations, but .USDZ works with .ABC files. The .ABC file was 1.2GB. The final step was the Xcode conversion.
Since volume meshing creates large meshes to begin with, and the Point-Level animation data for large meshes grows in size exponentially with more points to reference, once baked into .ABC caches, the file-size for the final export is justifiably large.

That comes to the second question, the .c4d file with all the necessary reference files would be ~16GBs, but that might change for better or for worse once the .blend file is converted to .c4d.

As for the scaling of the model, that could be a mess-up on my end, i apologize, it will be fixed in the next export. However, the metering system won't change the file size in any way.

You can expect the final video tomorrow, ready for the meeting.

Also, in my opinion, i would suggest looking into other options instead of AR Quick Look, that technology is still very young and undeveloped, and the whole system on which it's based is still very undocumented. There are many different options, which could go with all the demands you're interested, like Unity and a proprietary application, just to begin with.

Regards, ime ovde