I've been here! (I still am to an extent)
I was nodding like a nodding dog, when reading about your 'imaginary conversations' with him.
I've done this a thousand times over the past two years. I share your frustration. For me at the time, I was just so hurt and mad, that every time I tried to explain how he'd hurt me, it would end in us having a huge argument. We couldn't make it past the impasse.
Now I'm out the other side, it frustrates me that I didn't fully convey how hurt I was. Like you, I grew up in a volatile home, I get so worked up in high emotion situations.
I'm in two minds about this; no response is a response. And I have been on the receiving end of this many times through life, and it's always hurt the most.
The most reaction I got out of him back then, was when I refused to engage in a conversation about my MH (he was someone I had leant upon during my lowest points). He looked hurt. Really hurt. I had refused him the access to me, that up to then I had so freely given him.
I have pondered many a time, throwing one more line to him. To explain it once and for all, to apologise for my side, but also make it crystal clear where he fucked up.
But I think the ship sailed for that a longtime ago. My feeling here for you; is that unfortunately I think it has for you too.
BUT as I've outlined above, it's understandable why you feel the way you do. To me, it does sound like you have the 'upper hand'.
I don't know about you, but these 'imaginary conversations' I see as part of the healing process. It's your way of getting what's on the inside, out.