You want the speakers you mention at least 5 feet out from the wall. The more the better. Mine are 7.5 feet and the sound is glorious. I measure from the front of the speaker. Perhaps 13 is too much, but I would have to hear them. The rule of 1/3's works very well based on my experience and current set up. My room is 24 feet long and my speakers are 7.5 feet out from the wall.
I bet 8-10 feet would be ideal for you. You should still have body without bass overhang and great imaging a focus.
I bet 8-10 feet would be ideal for you. You should still have body without bass overhang and great imaging a focus.