@chaley: Thanks! Will report back as soon as it's up on GP
EDIT: It's up!
Bad news: I get a "Could not create folder(s)." tiny popup when trying to validate a custom full path pointing to my external sd card, even if said path already exists. Inputting something in the internal sd does work, though. Crappy Android permissions issue?
On the other hand, no issues when running on Calibre trunk, the streaming thingy seems to be holding up