I’m gonna say no. You won’t get the Atmos feel, sorry. From what I found on the rx700 it doesn’t decode Atmos. So while you can definitely use the presence speakers(unfortunately that’s how they refer to real too/height speakers iirc) it won’t be the same. Ime with them, it just makes the front stage a little taller. While definitely enjoyable, all it does is extract out of phase info from the LR speakers and adds it the presence speakers. As far as actually implementing Atmos, I’m definitely an advocate. Imo some Atmos is better than none. The problem with going beyond 5ch(bed layer) is that most of the time the bed is against the wall, not leaving suitable room for rear surrounds, and imo putting those speakers there does more harm than good. So I think 5.1.2 is the best choice in that situation. I believe I will do the same in my bedroom for the same reasons. 5.1.4 is much more immersive since you benefit from front to back overhead panning, and better object placement etc, but if the speakers can’t be placed correctly than the compromise is too great. IMO.
So, you’ll need a new AVR. And if you go that direction I would set up 5.1 with surrounds a little above ear level when propped up against the headboard, with height speakers somewhere between directly above the knees or feet. Some Dolby literature suggests keeping them the same width apart as the mains but Ime it depends on the ceiling height, as Atmos is all about angles, not arbitrary placement rules.
