yea the builder assured me that “these guys are great, they do AV for bars and clubs” or something like that. So yeah, sorry, but the thx pro is going to get the atmos in the living room job. At least he will understand where I’m trying to go with it.
Don't trust anything a builder says. Do you own homework.
I have now built and framed in two AV home theaters now. The first in the remodel of our Lake home on Benedict Lake in 2005 and in our new home that as built during most of 2019.
Your room is identical in size to the one I did on Benedict Lake shown below.
The new theater is a bit bigger all the way round, with 9' ceilings, and has room for three rows of seats.
This is a link to the build thread. This includes the great room and family room systems as well.
If you want this to be a success, you need to be heavily involved yourself during the whole construction.
If possible try and build it so you can get behind the equipment.
The whole process starts with carefully drawn up plans, including detailed drawings.
Make sure ALL AV cables go in conduit. Never just run any AV cable in wall not in conduit. If you break that rule you will regret it.
I think it is a good idea to make the AV room also the hub of your home ethernet architecture.
You will need to work closely with your electrician. Plan the ground plane of the whole home and integrate it your AV equipment plans.
For light dimmers use Lutron Maestros as these have the least RF generation. Keep dimmers on their own circuits, and do not interconnect them. Our electrician did put a couple on the same circuit, the family room and the stair lighting dimmers, and it made a Hell of a racket, until we got them separated.
Those all all the tips I can think of right now. But I did document my new home build extensively.