Interesting stuff, Arthur!
It's a bit disconcerting how much difference the different mics make, although in mids they seem more similar. Are the other mics you used directional or omnidirectional? When I did the test, I set my own mic to omni thinking it would be less coloured that way.
But I probably need to get myself an MM1 to do this properly 🙂
Looking at your EQ settings, it seems that EQ has a bit of a low resolution in the lower end (in terms of number of bands) and I suspect one often needs to have some pretty precise cuts there to fix acoustic issues there?
Curve-EQ seems slightly better there, but maybe also not precise enough, although it did make a pretty drastic and specific cut in the low end exactly where I expected.