Typically one will create an equilateral triangle of 6 - 8’ away from the back wall. So I would start three feet from the short back wall and in 3.5’ from side walls. This should work great as a starting point. Not having a wall behind the listeners position is great, no problem with reflections behind. Some side wall treatments may be required. Sounds like a good space. Do not position equipment between the speakers (only amp). You want direct lines behind the amp and off to the side for your components.
Where to place my two channel in new room?
