I have a 5.2.4.
Actually 3 subs. 2 are LFE connected, 1 for the front L/R and 1 for the rear L/R. The 3rd sub is connected high frequency only directly to center channel speaker terminals. My 4 heights, I am sitting basically in the middle, a little closer to rears. I have the 4 heights adjusted up 3db after Audessy correction.
I have said many times the biggest bang for the buck compared to anything in my home rig was the bass traps, side absorbers and rear diffusers, all from GIK Acoustics.
Emotionally, so far, I have been listening to Dolby Atmos to almost two years now, is the lack of satisfaction. The mixes are all over the place, whether it be movies or music.
For beginners the 5 on the floor and at least one sub are paramount to a successful surround listen. The heights are of course extremely rewarding. I remember the first Dolby Atmos movie I bought, 1915, I think there where two scenes where the heights kicked in. Of course there are fantastic examples of Atmos, Abbey Road, etc.
What seems to be a common thread in my listening to Atmos (4) is when it is a lack luster height experience, the two rear heights seem to be the most active, this is not the rule, just an observation.
So, all that said, if based on my experience, I only had a choice of two heights, I would put them behind me. General rule is try to make your heights line up with your floors, and situate 1/3 to 1/3 in ceiling, more or less and get your seating as best you can in middle, again, my seating is a tiny bit closer to rear heights.
The 7 point speaker configuration on the floor is mostly fluff, sound redirected. Keep in mind 99% of all surround recordings are 5.1, 4.0, Dolby Atmos, it is not common to see a 7.1 option.
Glad
@RustyStatic you are having fun with your new adventure, I find it so rewarding to scratch and claw through information I don't understand and eventually come out the other end, highly rewarding.