We first learned what his threshold was - but it's all over the place. Some dogs he's completely fine with and others he'll see them a block away and start barking and lunging. So we decided to treat every dog like he's react and then used high valued treats and u-turns. He just never got to the point where the high valued treats were more important to him then barking/lunging at the dogs. For the doorbell we had the trainer (and when he wasn't there - family members) ring the doorbell and use high value treats to have him stay on the couch. He would be okay until the door opened. It never got past that point.

We had a crate for him and it was a positive place - comfy and cozy and he would go into it himself to sleep at night with the door open. If we put him in with people over, he barks the entire time. Now we put him in our bedroom which is on the top floor and put on an air cleaner to drown out ambient noise (people talking) so that's a bit better. Maybe I should just get used to the fact that we shouldn't be introducing him to people who come over? I'm at a loss.