I've finally got the Twyne CLI client working, and it's churning away uploading all of my past photographic archives (from Piwigo at the moment, 90 GB). The work for this has mostly been done before now, but I didn't get back to it to actually tidy it up and set it running. Hopefully this will set me off further down the path of actually having everything a) in one place, b) organised, c) backed up, and d) actually useful.
I'm not sure if I'll tackle the export-to-Commons feature next, or sort out some of the UI bugs that are annoying me (like being able to zoom in on a photo). At the moment, I'm just poking through old photos and randomly fixing up metadata where I can; certainly there's some UI tweaks that will help with that process.