I have been using a 6" training tab (it is basically a tiny leash) in the training room to allow me to easily correct him without a leash dragging on the ground but also without hurting my fingers by trying to grab his collar. He at first did not like the tab and when I went to correct him he reverted to an old back-talking habit of trying to grab the leash with his paws, however with the leash being so short he actually ended up engaging the collar and giving himself a pretty nasty correction. He didn't try back-talking again. His only issue with off leash is that he gets so wiggly and happy that he is just a tiny bit sloppy when there isn't a leash on. The leash makes him calm down a little and seems to give him a sense of propriety.
Tomorrow we are doing more with off leash but other than his exercise we are keeping him inside. It will simply be too hot tomorrow to do much with the dogs outside.