I may have missed something but have you tried angling the center down a little bit more towards the listening position? It looks like it is shooting straight out above the TV and no where near the listening positions.
I am still looking for a suitable Grover picture....Just got back from 4 days in the Rockies.
I have 2 rubber door stops under the center and it is angled down toward the seating area, pretty much about head level for us.
If you notice there is a cross sitting on top of the center. That is the angled side so it has to be raised in the back or nothing would sit on it.
I'm gonna change my avatar to Grover for a while so you can see it and if you like it I'll send it to you. I like the one I'm currently using so I hope you see Grover soon