Is there anything wrong with using a conical horn for the midrange, say a range from 300Hz to 1.6KHz?

People are always reccomending Tractrix or Hyperbolic for the midrange, but never conical. Some of you might remember I built two Tractrix horns for some Alpha 6's I've got, they perform great, but I just found today in a Hornresp simulation that if I built a conical horn then the HF extension would be even higher in a horn of the same size and is still flat which is good.

Are conical horns the straight sided horn? Is the Unity horn a conical horn?

If its a straight sided conical horn, it isn't a CD horn is it, I could make wider coverage angle/dispersion in the horizontal than the vertical planes if I wanted without ruining the hornresp simulated response?

So whats the pro's/con's of a conical midrange over a tractrix midrange horn? I remember reading on this forum a few months back that conical has lower THD/phase distortion???

BTW: What does the FTA box mean in hornresp? Its for conical horn mouth flare tangent angle when I'm simulating a conical horn, what use is this? Also why doesn't the conical horn simulation show the flare frequency it is always 0.00Hz, although it doesn't affect the simulation really.

Thanks!
Adrian