Berliner Philharmoniker concerts performed for their Digital Concert Hall online streaming service are now mixed for immersive sound. They happen to be using Dolby Atmos, but the mixing principles and results are much the same as for the Auro-3D technology harnessed by VSL's new MIR-3D. (I've heard say that Auro-3D gives somewhat more realistic results than Atmos in the Height dimension; however, for orchestral concerts this claimed potential advantage is probably not of any great significance.)
My suggestion here is that MIR-3D users, while launching into the new world of immersive mixing, might enjoy and benefit from listening to recent and current Berlin Digital Concert Hall concerts mixed for immersive sound. (I think they said their last 3 or 4 seasons have been mixed this way.) I've just signed up for the forthcoming '22/'23 season and look forward to hearing some of my favourites mixed for immersive sound.
I don't have a multidimensional speaker setup, nor am I interested in having such a thing. I find that for orchestral music, good immersive mixes are wonderfully satisfying on headphones. Direct and spatial depth in 2 dimensions satisfy me very well in terms of the sense of immersion.
For anyone interested in Berliner Phil's approach to immersive mixing, here's a short YouTube video in which Christoph Franke (Recording Producer) and Andreas Wolf (Balance Engineer) give us a concise overview of their current work at the Digital Concert Hall. (In German with English subs.)