I just saw your thread about dipole treatment written in Sept 2019 and wanted to chime in if you hadn't already pulled the trigger but it seems your $1K budget grew and that you're a happy GIK customers - kudos.
I own SoundLab dipole electrostatics and concur that diffusion on both front and back walls with bass traps in the corners is a good general rule of thumb. I found that sound quality was affected by distance from speaker to the front wall behind it. Hopefully you've been able to experiment with distance and also listening position distance and toe-in as equal partners to sonic optimization. Enjoy. ...kevin