My friend , down @ WHPS has done this , many times:
https://www.seriouseats.com/sous-vide-duck-confit-recipe
""" not as tender and delicious as the duck cooked using the settings that I ended up pegging as the ideal combination of temperature and time: 155°F (68°C) for 36 hours. ""
he swears by this , and Ill be trying it soon.
A P.S.: one thing ive learned about SV : its very forgiving , once you are in the Ball Park
of the results you are looking for.