For the sake of my health I had to make an urgent move and for the time being will have to do with a much smaller house with a much smaller living.
For now I came up with this setup:

Note: my drawings are not accurately scaled.
The 103cm from the wall is about 1/5th of the room's 508cm. Toe-in now is 4cm.
Putting the speakers at the opposite wall is not possible because of the back door that has to be frequently used.
Putting the speakers in front of the windows as I understand is not preferred but it would have the benefit of having more sound to the kitchen what I do enjoy during cooking.
The sideboard on the left wall has the TV-set on it.
The house came with laminated floors and that combined with concrete walls is good for horrible acoustics to start with. I have put down carpets in the seating area and under the dining table and a couple of pieces of Styrofoam I had at hand at the wall behind the speakers. This improved the situation.
The two windows will get net curtains.
There are low frequency problems. Particulars tones are very emphasised. Like the bass on J.J. Cale's 'Cocaine' and I also had the issue with a Jimmy Smith recording, a particular tone from the Hammond organ.
On the other hand, there is no real low bass. Even when crancked up the sub-woofer is not heard. It does work, I can feel the cone vibrating. I have the same with a less refined sub-woofer connected to the TV-set: no low.
I can only suppose the wave-lenght will not fit inside the small room.
In the highs, I miss a sparkle. I had first connected the big amp, then the Advance that does sound fancier but I still miss a sparkle from the highs.
Not sure if it's me or something else.
Good thing about the house is that the division walls to the next houses are double and separated.