That's an awful lot of 120L crystal in there, but it is not out of control. If you've worked with that stuff before, and you know what you want, then go for it. If you have not brewed with 120L before, then you might want to back off to 8 oz. and see if you want more later on.
It is in an interesting recipe, but I might back off the 120L crystal and add something else, maybe some of that dark Munich you were talking about or some crystal in the 50-60L range. I would probably go more with the Munich, though, as I don't know how much caramel I would want in something like this.