I checked the FAQ but it listed a directory that doesn't exist either in the Finder or the Terminal. I'm having no luck at all using Spotlight to find files modified in the relevant timeframe.

I bought the game a week or so ago, and it's using Wine to do it's thing, if that helps.

Should be ~/Library/Application Support/GOG.com/Planescape Torment/Save or thereabouts.

Confirmed:
HD / Users / <username> / Library / Application Support / GOG.com / Planescape Torment / Save

I also figured out what is happening. I noticed that save game folders are being moved under other save game folders, instead of being in the root level of the Save directory. I created a shortcut to the Save folder and a made a secondary location elsewhere in Docs to save off copies of the save games. I'll pop out every hour or two and make sure I have a couple of recent copies.