Soundstage width of my m4tm has never been its strength, as sound hardly ever extends beyond the sides of the speakers. I have them now crossed facing me directly, but will give your suggestion a try since being holographic is definitely a plus. Rmbed I tried this in the past, but ever since adding a sub into the system, I've never experimented again.
The thing with this article is that these results are for traditional boxed speakers, and over the past year I've realised that open baffles react very differently to boxed speakers. They seldom load the room, and also 'first reflection point' issues off the sides of the speakers is hardly an issue, because the sides of OBs are basically null points as the front and back waves cancel each other out.
This may be why the soundstage doesn't extend very far off the side of the speakers, and also left me wondering at the start, why there was little to no improvement when I added diffusion panels at the first reflection points on the side wall (made a lot of diff when I had my bookshelves).