I just don't think you can make as clear-cut a distinction between the Church and Israel as the dispensationalists would have you believe. It's a lot more complicated than it seems.
I'd say two things. First, Paul seemingly had no such confusion. "Give no offense to Jews or to Greeks or to the church of God" (1 Corinthians 10:32). He clearly, self-evidently, assumed that his readers would have no problem in distinguishing the three groups. (Imagine the chaos he'd cause saying this to a neo-RC "Reformed" colloquy!)
Second, if you want to go all squishy and spiritualizing and allegorical, be prepared to tell me which aspects of the Christian Church are denoted by "the tower of Hananel," "the Corner Gate," "the hill Gareb," "Goah," "the whole valley of the dead bodies and the ashes," "all the fields as far as the brook Kidron," and "the Horse Gate toward the east" (see Jeremiah 31:27-40). And that's just for starters.
You don't seem to think very deeply about anything I write to you. If you're only going to think deeply about one, this would be a good one.
Dan