If you're going to end up with x.x.4, I would start with 5.1.4, while 4 overheads is usually always preferred over 2, it's esp. so with Height speakers.Tagging for future reference/questions. So glad I found this thread, as I've been trying to decide just how I'm going to install additional speakers to take advantage of Atmos/DTS-X on my new Marantz SR7010. Was going to start with Atmos add-on up-firing speakers, but after reading this thread, I'm going with front (and eventually rear) heights. I currently have a 7.1 setup. Until I get a separate 2-channel amp in order to run 11 speakers, would it be better to run 7.1.2 or 5.1.4 with my existing 9-channel AVR?
And even more so with the approved FH/RH combo. You need the 4 to fill in the overhead center area above you.
That, and the overheads actually get used more than the rears in most situations.