I'm sorry your single boy isn't getting along with the other boy. I don't think it's always necessary to do 24-hour bonding, but I don't think I would do bonding sessions of only one hour. They won't have time to get comfortable with each other in only one hour, as they'll need quite some time to establish their hierarchy before they can simply spend time together, and they can't move past that in only one hour. If you can do longer sessions in the weekends, I think I'd only try to bond them in the weekends and leave them be during the week, as it'll just be unneccesary stress to put them together for only one hour.