My Roksan Darius MkIV (from the glorious 90’s) were designed to work like that, in a 90 degree angle. In fact I am listening to them right now, and the soundstage is huge with pin point imaging. Although very tough to set-up, all efforts were rewarded with sublime sound: they completely vanished in the room, and deliver very tight bass, clear and sweet treble.
That said, I never experienced that extreme toe-in with any other speakers, in fact, I prefere no toe-in at all with my Thiel, Totem, Kef and Quad speakers.