Beat, thank you for your explanation and the helpful links. In particular I found your video on using the Hofa plugin interesting.
It seems my ear told me correctly that you're using traditional panning controls for azimuth positioning, not the ultra-realistic "binaural" type of positioning, e.g. as provided in Logic's mixer and in 2C Audio's Precedence plugin. If perhaps one day you switch over to this new type of localisation, I'd be fascinated to hear if your already excellent mix spatialisations become even more superb.
In recent years I've become a 'heretic' in regard to the widespread belief in the virtues of convolution reverb (I don't fully agree with the assumption that acoustic spaces can always be faithfully modeled as having linear and time-invariant reverberant properties, nor am I fully convinced by the ingenious techniques for interpolating between the positions at which actual IRs were originally captured).
To my ear, that ever-so-static 'crystalline corona' which all too often attends mutliple convolution reverbs tends to wreck the magic of a mix - no real acoustic space filled with people is ever frozen solid like that.
I'm very impressed by recent improvements in algorithmic reverbs, which I'm now exploring and exploiting in combination with "binaural" positioning for my mix spatialisation. Also I've found it fairly easy to combine Synchron Strings Pro (Full, using room mics) with SyDimStrings (100% dry before my spatialisation), with good overall spatial definition and coherence in the mix.
Not least, I'm now very happy about the much lighter load on my CPU. I'm sure there would be a good market for a purely algorithmic successor to MIR if VSL were to venture down that avenue.
I agree with you that in setting up and tweaking our mix spatialisations we're engaging in a somewhat dark art; and so of course experience matters a great deal. No doubt that has a lot to do with why I like and admire what you've achieved with your mixes.