I'm happy to hear that folks are trying the no contact and finding it useful.
The no contact is exactly for that, to keep you from saying stupid stuff. I do encourage letter writing, I did a LOT of that. Just don't send them. If you still need to say those things, you can say them at the end of 40 days. I usually didn't need to say much.
I tend to ruminate, and go over and over in my head what I want to say, what I wish I'd said, what I'm gonna say. I started writing them down so I wouldn't forget, and that awesome little act would let them get out of my head so I could move on the other things I wanted to say. It was wonderful processing. and usually, by the end, I'd be okay. Sometimes I'd still say stuff, but not nearly as much as I would have said after a week.