2 way or 3 way
I think you'd find that the sound would be a bit too "bright" with a surplus of tweeters, but that's just my humble opinion. I'm sure the folks with the gazillion watt systems will chime in with advice on this.
correct but your staging needs to be at ear level which is why people started putting tweeters in the pillars. with good staging you can overcome the tweeter driver separation


