I think it's a great idea, but I would mortise both sides on the narrowest setting. I would glue the domino in one leaf and gently sand the edges of the other end to ease entry. If alignment proves too difficult, then at least keep one pair of mortises on the narrowest setting or the leaves will not line up properly.
I would only use the narrowest on 1 domino per leaf. After all, how is any different from domino-ing anything else, sans glue?