About 6 months ago I set up some floor-attached angle jigs perfectly aligned together with the wall behind them. Angle matching between the speakers is determined by measuring the distance between the leading speaker edges and the wall behind. Speakers can now be in perfect alignment as to distance from wall and angle. This makes fiddling with imaging much easier. With Cornwalls very slight adjustments can make big differences in imaging, tone, treble response, bass response, etc..