Indexing: Speed & Limitations

I have around 10 TB of FLAC and SHN fles on my NAS that I am currently indexing on a fresh install of the latest version of Volumio.

With respect to indexing, is there a way to index these files on a different PC as opposed to the Raspberry Pi 3 B+ that I am running Volumio on and then copy the index file over to the Pi? I imagine that this task is very taxing on the Pi and could be completed by a much faster PC on my network.

How large can I expect the index file to be when it completes? I want to ensure that my mircoSD card is large enough to hold the index file.

Is there a limit to the number of files I can index for my library?