Cook at 180° for 10 hours. The corned beef will be very tender and short of shredding. This is the sweet spot for me because it is much easier to plan and prepare to cook over one day than two.  I also like that the meat is just short of falling apart. It is very juicy, but still slices into nice clean pieces that are great for a traditional Irish dinner or corned beef sandwiches. The beauty of sous vide cooking is the ability set the time and temperature and get exactly the result you desire.