Don't be too shy - MIR mixes react to mastering as fine as any other mix. :-)
EQs: My first choice always is MIR's own Master EQ, as it relies on the same design as our Vienna Suite's Master EQ plus a few enhancements (like notch filters). Personally I would stay away from linear phase EQs as soon as you plan to do serious processing in the low end, as the system-inherent pre-echoes will become quite obvious then. For treble adjustments they are fine, though.
Dynamics: In addition to the common compressor/limiter combination, I love quite a bit of saturation on my mixes. Good tape saturation will do the trick, but you could try the Vienna Suite Compressor in "FAT"-mode for starters.
Stereo Imaging: As MIR mixes are very similar to recordings derived from coincident microphone setups, they show great results when using the Waves' S1 for some Gerzon shuffling. Values as small as 1.1 or 1.2 will make a good MIR mix bloom.
... hope this is some food fo further experiments ;-)
Kind regards,