There are 2 things to consider. The 7100 will play louder than you can tolerate in your room.
You said in your opening post “I want clarity and authority and spectacular special effects.” An
important part of the special effects comes from having a system that is able to play a sound track
or music without clipping off any of the loud passages (transients). For instance, the gunshots in
“Open Range”, which can be spectacular on a good system. It takes a lot of amplifier power to
be able to do this. The 770 would be better than the 7100. The 790 would not be too much, even
on speakers of 90dB efficiency. Only you can decide how much the special effects are worth to
you. I have a 7100 driving Rocket RS1000s (rated @ 90.5dB), an RSC200, and RS250s with an
SVS PB2+. The gunshots from “Open Range” hit me in the chest in a very dramatic fashion. I
have to believe that they would sound even better with a 770 and better yet with a 790.