Had the 1.6 and did exactly what you are considering - biamped with 24 db slopes. This was a few years ago and I can't remember the xover frequency but I am guessing it was around 1.5k. It was much more transparent with tighter bass. I played with the phase of the tweeter and I think I preferred normal phase. It's pretty easy to try this yourself. The speaker also becomes much more efficient.
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