I would strongly suggest getting another surround speaker to use for the rear center surround. Its been my experience that a number of movies even with the trick Jason described above, don't decode properly. With the increasing number of movies in DD-EX, I have found having the extra speaker an excellent investment. Given your preference for NHT, I would look at ebay for a used VS1.2 or a Super Zero/One.
_________________________
Living Room 24x18 open 1/2 flight up to a raised dining room/hall 24x12
Outlaw 976 pre-pro running 5.1 system
Outlaw 750 for Artison Masterpiece LCR and 2 NHT SuperZeros rears
Velodyne Servo FX-1200
LG OLED65C8PUA via HDMI2 to/from 976 HDMI ARC
Roku Ultra
Samsung BD-D5500 BluRay
Amazon FireStick 4K to 976 Aux HDMI input for Amazon Music Ultra