I think writing it down and sending it to him is a very good idea. TBH I haven't done that myself and DH seems to be able to either conveniently forget what I've said or he twists things around until I either can't remember exactly what I did say or it changes into something that suits his purposes. So I'm going to write them down myself! Not to send to him, we aren't 'there' yet. But just so I remember my 'exact words' myself!
I'd just review it carefully and find some way to say that you reserve the right to 'adjust the boundaries' if you find it isn't doing what you intended it to do or it simply doesn't work.
My DH is supposedly going home on Friday, but I haven't confirmed that 'officially'. But he's already discounting one of the main boundaries I've said regarding possible reconciliation; being 'reliably sober for a period of time'. He's twisting the words to the point where he can discount it as 'being unreasonable'. But he won't specify what is unreasonable about it nor will he make a 'counter proposal' as to how he intends to prove that he really is embracing sobriety. Which of course makes me doubt that he intends to be sober at all. But I think his main reason is to get me home 'now' rather than allowing time to see how he does. He also said something about how 'slipping up now and again' doesn't count as not being 'reliably sober'. Really? I counts with me!!!
I think the reason he's so desperate to have me move home right away is because of the difficulty and expense I had getting my things out when I decided to get my own place. I think he figures I don't want to go through that again. He's right. I don't. That's why I'm making no plans to move back. Ever. I've told him let's sell the house, I stay put and you get a flat nearby, and we take it from there. So now he's putting multiple objects in the way of selling and portraying them as 'mine'. In reality 95% of the crap in the house is his. I got most of mine out 6 months ago. But when I point that out, he completely blows it off and keeps trying to make his shit my problem.
Ugh! Sorry for the derail. I guess I needed to vent.
You do whatever you need to do to protect yourself emotionally and physically. WE MATTER!!!