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.
I asked Dietz about this a while back. Specifically: what the CC7 should be set to when using something (either VI or SYN-zed with the SYN-zed impulse turned off) in Mir Pro. He said that as long as CC7 is set to the same value across the board for all instruments, it shouldn't matter *what* it's set to as the natural volume values (which are just adjustments in gain, not CC7 values) will then all be based off the same CC7 "foundation". He did mention that Herb tweaked the natural volume settings with CC7 set to 100 (as he recalled), and I decided just to go with that since CC11 increases in granularity the lower CC7 is from its max value.
What I mean by that is that Expression has iterations from 0-127, but within the volume range defined by CC7. If CC7 is set to 127, Expression and CC7 are basically the same thing. But if CC7 is set to, say, 100, then Expression gives you 128 iterations *within* the 0-100 window defined by CC7. So, each step or iteration of CC11 then results in a finer volume change, which I enjoy as "smoothing" on top of VelXF (CC1 in my case).