I'm loving all the info on this thread, really helpful about the rum drinking AS!
The code word sounds like a great idea, but I would build in some sort of ground rule about coming back to the conversation later, maybe with a timeline to it. A big problem in my M has been stuff being swept aside and ignored. It's very sensible to say when one of you is triggered, because talking then is fairly pointless, but the issue still needs to be addressed when you're both calm again. I really regret some of our conversations where I just kept pushing stuff in hope of some sort of resolution and my H just shut down. In return, I tend to run away when I get triggered and that's also not very helpful particularly when my H is sensitive to abandonment. I would like to institute some sort of idea like this with my H when we get on firmer ground.