I just started trying it out on my tab (not ready to dare it on my outdoor phone). It works well, within the constraints, of course. I only now realized that I can't sync Locus data via SyncThing - for example, I synced my Locus/data/media folder like that, but SyncThing doesn't accept Android/data/xxx as source. Thank you Google!

Anyway, one more question about the storage space change:
You offer to switch between internal and external SD for specific directories. However, would it be possible to use
both, at least for maps? Or is that prohibited by Google, too? I do have a lot of maps, currently the most used on intSd, the others on extSd. Of course it would all fit on extSd, but especially the OruxMaps format (database) are faster from intSd. So it would be great if there's a way to use both at the same time. You don't even have to provide an organizing tool, at least not urgently - I can move the data without problems by attaching the MicroSD to my Windows machine. So no changes in the UI, there's still the "main" directory for maps and mapsVector, just also use the data from the not-selected directory if there is any. Possible?