I have exactly that layout in my room
I had my SVS out in the main seating area for a while, kind of to the right of your picture, against the right hand wall, and the bass was okayyyy but nothing to write home about.
When I moved it into the alcove it seemed to provide a real boost to the output!
As above, it can be a bit peaky across the room but as I only ever sit along one row of seats, I'm not too fussed if it's louder in the opposite corner and quieter halfway down the room, as long as the output is decent at the sitting position!
In my head it is 1/16th space - i.e. sub on a floor is half space, sub on a floor next to a wall is quarter space, sub on a floor in a corner is 1/8th space... so with an additional wall on the other side, it must be effectively 1/16th space, I think?? Therefore it should provide a good boost to output, albeit slightly peaky at points!
I have Audyssey EQ32 and it has helped tame some of the resultant peaks in frequency response