I just got done making @Kenji’s 10 hour corned beef.
It still needs to chill in the fridge for 24 hours before slicing and serving, so I’m on pins and needles 
The real downside is that usually, when I cook something for 10 hours (braising, roasting, etc) the whole house smells of deliciousness; now with sous vide, everything is sealed in the bag, so not so much.
Of course, that means all the deliciousness is sealed in the bag, so maybe that’s not a bad thing 
You can pour the juices into some water to cook the cabbage. That will smell up things a bit.
Cooking smells are lovely but sometimes they make me hungry and anxious for the food to finish. I don’t want to smell delicious when I have to wait a long time to eat it.
Cabbage is a whole other story. When I was young the smell of cooking cabbage, combined with less savory aromas having to do with basic hygiene was very strong in some buildings. IMO sous vide cabbage is the best. No smell, great texture/taste, and doesn’t make a great mess wrangling it out of pot.
How about sous vide cabbage, in the juices from the corned beef?
What would be the best time & temperature?
I’d try 194°F for about 45 minutes.