If I were you, I would try the Bergger BRF 200. It's a "copy" or a remake of the Kodak Double-X. I love this film. I use it a lot.
You can also try Foma Films. They are pretty good. But Efke is bas quality, because emulsion is very fragile.
Actually, everything I've read about BRF 200 indicates it's supposed to be a copy of Super-XX.
The movie film "Eastman 5222" is Double-X - quite usable for stills - "short ends" are available inexpensively from film stock distributors (35mm only, though).
i can't wait to take a picture of my thumb with this beautiful camera.
- phirehouse, after buying a camera in the classifieds