Hi,
i have pretty much come to the same setup as you. Probably for the same reasons. Theatre, BL90s and 3 pairs of BL3s in my rented apartment will shortly become Theatre, BL90, 2 pairs of BOC86 in a ceiling, BL8s as rears in my new home where drilling large holes in walls and ceiling is on my dime.
A few points I can make:-
1. Despite their compact size, a 5.0.4 system has a lot of B&O clutter (either in the corners and a problem for wiring……..
2. I think Celestials (if you are able to) reduce a lot of over the top B&O jewellery clutter and I believe they are cost effective (about £2600 per pair of BOC86 plus BeoAmp2)
3. Although enthusiastic about the BL8s I have also purchased and listening as Beosounds, they sound very good….but they are now on personal reflection too big as surrounds if ceiling or wall mounted heights - unless you have a big room. My initial expectation was these speakers were the diameter of BL6000/BL28s. Instead….they are stubby BL9s kinda diameter.
4. I plan to set up my Theatre Atmos system as per the Dolby guide with overhead over the sofa at 45 degrees front/rear from the listening position.
I don’t see it as uber-critical and think the Theatre will work out the math etc…for an exceptional surround system