Yes, using 1 it's not so bad but then you're back at having a 6db drop in doubleing of distance for the tweeters. Using more it's usually the c-t-c spacing of the drivers in the array that will determine at what frequency comb filtering starts setting in. On using more constant dir. horns usually the mouning flanges are going to add about 1/2" to an in. more to the c-t-c spacing in which comb filtering will start setting in at a lower freq.In pro sound most line array horns I've seen have a dispersion pattern of 90x5 or 90x10 deg with 2-4 1" drivers mounted on 1 horn.
HTH