It works! I have a loopback without sacrificing one pair of ports and I can scale and send CC back to Midihub and map it however I want!
I have created the loopback with THRU enabled in the instrument which is my master clock (it’s always on). This instrument is using Channels 1-8, and I send loopback to Channel 16, so the CCs that I’m using don’t mess up parameters of the instrument.
With a few transforms I translate the CC to another value which gets also scaled to new CC which will be used for mapping. Then, the new, scaled values are mapped to a filter, which is passing only the MIDI information which is needed, e.g. notes, not clock etc.
Now I can use a single knob on my MIDI controller to completely change behaviour of Midihub, as if I had multiple Midihub presets assigned to the knob. The knob is scaled to send 1…16 values, and that allows me to precisely select a value of the knob. Each value of the knob is switching to a completely different routing in Midihub, as if I had 16 presets in Midihub.
More than 8 presets, easily and precisely selectable from a single knob of my main MIDI controller, without losing a pair of ports - three birds with one stone 
The setup is a bit complex and requires some tricks to make it work, but it’s feasible.
I hope I’ll have some free time to write down how this patch works and how to set it up, if anyone is interested to see it?
Cheers!
U