In general, for .4 Atmos, you want Top Front and Top Rear placement. They do not need to be specific to the mm when it comes to placement...
We all have imperfect rooms and have to do the best with what we have!
You have a good amount of space to work with. But according to the image in your original post, your placements are WAY off of ideal for those two locations.It also seems like your seating is super close to the front wall.
Perhaps, please detail in measurement alone, Width between L/R main and Distance to LP. Compare that to the Dolby specs for 7.1.4 set up. If you move the Elevtion speaker to the side wall, in the spirit of maintaining the "intended geometry" of separation between Atmos Layer and Bed Layer, as well as staying as close as possible to the distances for the Atmos speakers from the LP, I think you will be fine.
My personal approach: I like a more isosceles triangle for LP to Main Speaker placement. Once you have that settled
To Your Liking: set the Surrounds and Rears as recommended by Dolby, or as close to it as you can. Surounds should be slightly behind LP by ~10º and slightly above ear level. Rears should be clser together than your mains, and behind you at the same level as the surrounds. IIRC, Top Fronts should be in front of the LP by a few feet, but not as far forward as your mains. Top Rears should be behind LP by the same distance, and not lined up with either your rears or Surrounds.
The Separation of channels is what helps give the effect.
Again, using your first post image: I would move LP back a little, move Top Front closer to New LP According to Dolby Spec. I would Move Top Rear Closer to LP according to Dolbe Speac, and move rear surround slightly closer together (and not in line with the Mains.)
Hope that makes sense and helps out some!