I second Abex's thoughts.
It all depend on what you like to listen to.
Me, at the narrow end of the room, (dimension is same as yours except the H at 12 feet), stand diminutive Proac 1SC on rigid stand, 3 feet away from the rear wall. I love the visual unobtrusiveness of it all, and best of all, paired with single ended triode, it emulate, just the way I like, the purity and lushness of the orchestra and voices and the space where it is recorded. Personnelly, when I went full range, I used panel speaker, (as I will again soon when moving) otherwise I prefer monitor on stand.
It all depend on what you like to listen to.
Me, at the narrow end of the room, (dimension is same as yours except the H at 12 feet), stand diminutive Proac 1SC on rigid stand, 3 feet away from the rear wall. I love the visual unobtrusiveness of it all, and best of all, paired with single ended triode, it emulate, just the way I like, the purity and lushness of the orchestra and voices and the space where it is recorded. Personnelly, when I went full range, I used panel speaker, (as I will again soon when moving) otherwise I prefer monitor on stand.