If the video files are moved to the channel directories so they can be mapped to the channels created in TubeSync and the video files have the YouTube IDs in the file names then yeah renaming them as a batch command should be possible. Downloaded file size should be fine as well if it's literally just size in bytes in disk you want.

This might be bumped to a 1.1 not the 1.0 release depending on how much time I find in the next couple of weeks.

Oh and feel free to create feature requests, I'm not going to consider any reasonable suggestions as spam.

No rush, I'm certain there are more important things you'd like to do. I realize I'm a bit of an archivist and might be an extreme use/test case and taxing on the software, so I'm pulling metadata only for everything before throwing my existing collection at it.

Extreme is good, far more likely to encounter weird edge cases :)

Automated renaming has since been implemented.

That leaves this as including the file size when importing a media item.