To add to Videodromes thoughts:
Anything under 6" from the back of the speaker to the wall is to close. electrostatic/Magnaplaners require feet behind them.
As an example, my paradigm's 60's are ~26" from the back wall to the back of the speaker.

The reason for a 3:2 ratio 'distance from': 'space between speakers' is to give a better sweet spot.

For a reference recording - I like to use King James - Harry James and his big band pressed by Sheffield Labs.
It is recorded in a church w/ one microphone. It is a live recording. A properly setup 2 channel system can discern every musician (left to right and front to back).
Pink Floyd is cool (Wall and Dark side of the Moon) - come to mind.

Telarc has several recordings that will work.

Have fun playin.....