133°F for 18 hours to 2 days
Update 2015.12.25: I only was able to do the shanks. The shanks were done at 133 for ~39 hours. The doneness was good. The meat was dryer than I want. It wasn’t salted but I think a bit of sail might have helped with getting the flavor better. But then again it might have made the texture worse. I am not sold on beef shanks. There were nice tendons interlaced with the meat but I don’t think they had enough of an effect on the texture to pursue this as something I want to make often.