All of the above makes me ponder my MirPro setup.. MirPro presets impose quite a bit of attenuation also for the sake of level balancing. Actually significantly more than the Synchron CC7 approach. I will have to do some similar testing both inside and out of VePro to see what results I come to. But I think in the case of using MirPro, I would set CC7=127 for all instruments and then set CC11=110, as @PaoloT is doing, for the wiggle room, but with out the CC7 compensation (since I will use MirPro's natural volume slider for that.
its not clear to me yet whether MirPro presets are calibrated already to take into account that Synchron instruments have CC7 set lower or not and then perhaps adjusts them a little more, but what I can say is that by default the MirPro attenuation with Natural volume is rather significant and usually feels like too much, so I will almost certainly be using some kind of trim plugin to bring it back up, but it also means that if and when I go to "Eleven" with CC11, there is more possibility of clipping something if I'm not careful. So that will be something to watch out for.
UPDATE: I measured the results of running this default Synchronized Trumpets through MirPro, and yes its calibrated to depend on the factory default of CC7=90 in this case. When running this Synchron instrument through MirPro instead of using the IR's in the instrument, with CC7=90, CC11=127, and MirPro using Dim Trumpet instrument preset as well as Mirx mode for character....the resulting level measured very very close to the above scenarios without MirPro...so conclusion is: they have set these MirPro preset's natural volume level to expect the level coming from the VSL CC7 defaults, as far as I can see, at least with this instrument. That's a good thing...but it means basically I could pontentially change all my Synchron presets to use CC11=110 as the home base, and either compensate with cc7 bumped up a little bit for each instrument or a trim plugin with +2.5db on the whole bus...and they should all work with the MirPro presets and the default Natural Volume levels. and those Synchron presets would still workout without MirPro in that case.