My suggestion for tweeter xover point is get the mid to play as high as possible and stilll sound good. Then bring the tweeter down to the mid. If they are drivers with a decent frequency response to begin with, only a few minor adjustments should be needed at that point.
Gain settings between the mids and tweeter being an important one of them. That statement correlates with my post above too, which is the minimalist approach.
a dsp running active is a barrel of fun though, if you're into that kind of thing.