Probably a very roundabout way of doing it, but I essentially copy-pasted the RTP into the game's folders, then checked against the database as I manually deleted files in the BGM and Animations directories of what I didn't use. Got the file size down to somewhere around 83 to 84 MB, though!
While I may be uploading this file as I type this comment, I must note that I did not test this demo with a computer that doesn't have the VX Ace RTP. If there are missing files, please make a comment here, or on the game-page!