How long and at what temperature should I sous-vide a 5.5lb veal breast?
It depends on the thickness of the meat and how well done you like it. There's an excellent reference here: http://douglasbaldwin.com/sous-vide.html#Beef
I cooked three boneless rib roasts sous-vide , about six or seven pounds each, in an insulated cooler at 137 for six hours, they were a nice medium rare. I know it's not the same but maybe that will give you some guidance.