tweeters with 250 RMS!? are you trying to break your windows? Or just your eardrums? That sounds like an awful idea.
Why not get an active?
Tweeters should be handling somewhere around everything above 4 Kh, but this is subjective to people's tastes.
I don't like to have my tweeters play much below 4k, I let my midrange driver woofers do that.
I still say get an active crossover just for everything.