The biggest fallacy in your logic is this: "You cannot obtain the same spacial configuration with a tower that is vertical." That is simply incorrect. A horizontally symmetrical speaker, (such as MTM, W(TM)W, or W(MTM)W alignments), will, by the physics of driver interactions, exhibit horizontal off-axis driver interference. There is a massive amount of scientific data to prove this effect. There are ways to minimize this effect, some better than others. An MTM will be the worst, while 3-ways with center mounted mid/tweeter arrangeements will be better. Nonetheless, there is NO WAY to eliminate the driver interactions in the horizontal plane except by using a vertical alignment of the drivers. Three vertically aligned speakers, all placed at the same height horizontally, is the unequivocally best arrangement for a solid, cohesive integrated front soundstage. That is why so many commercial theaters, as well as the most optimally designed Home Theaters use this configuration.Use a dedicated center speaker with multiple drivers (a real 3 ways).
If it has the shape of a sound bar, place it just at the bottom of the screen and tilt it 60 degrees up.
That way the tweeter is at the center, one mid range on each side of the tweeter and one bass driver at each end of the sound bar.
I even have one bass reflex exit at each lateral extremity of the sound bar.
You cannot obtain the same spacial configuration with a tower that is vertical.
The other fallacy is this: "If it has the shape of a sound bar, place it just at the bottom of the screen and tilt it 60 degrees up." Placing a CC below the screen can never work as well as placing it behind an Acoustically Transparent screen. While it's true that an AT screen will have some acoustic deficit, the newer woven screens trivialize that problem and never require the amount of EQ that can potentially damage tweeters. Here's a graph of the attenuation caused by the Seymour AV woven screens:
Virtually all speakers can handle a dB or 3 of HF boost to compensate for the screen. That is no more than what happens with a click or two of the treble control, or the flip of the treble switch on the speaker itself.
Also angling it up at 60 degrees may or may not be the most optimal angle.. The key is to angle it enough so that it aims at the listener's ears.
While using a horizontal CC below the screen can be made to "work", with results that many users find acceptable, it is not, as you seem to think, the most optimal or best arrangement. That would be reserved for the 3 vertically aligned speakers, all at ear height.