I think drawing blood is certainly where I would intervene. As much for Juno's sake (however much she doesn't care) as to start teaching Sawyer to let you call him off that kind of play. That way if he's playing with another dog that same way, and you can see that dog isn't going to be as tolerant as Juno, you can keep some control over the situation and keep him and everyone else safe.
I would also, if you aren't already, try to find some other adult dogs you know and trust for him to spend time around. Ones who aren't going to hurt or really scare him, but who are going to draw the line a little earlier than Juno. I really credit Gusto's fantastic dog skills to Meg and my friends' adult dogs who did such a good job of teaching him to back off when asked, without ever making him feel like he had to be defensive.