If you can set up at the 1/3 position as Toocool4 showed, even temporarily now that the couch has moved it may help determine the best case scenario for short wall set-up. Some of the best imaging systems I've heard were positioned so you can just see the front wall room corners on the inside of the speakers, from the listening chair. Also, the later arriving reflections from the front wall should enlarge the sense of space.
The long wall set-up is always worthwhile trying. Since your chair will have to be close to or against the rear wall, substantial diffraction will be needed on the rear wall.
And as always, equipment matters. High quality tube amplifiers, dacs, and preamps (if you use one) can greatly enhance the stage. As an example, some dacs will provide super high resolution but a front row or forward presentation, while others may have a mid-hall presentation (if your speakers/room can support it) but perhaps less resolution.
