I've been using a little Novation Nocturn controller for years - with Pro Tools 10 and earlier, Reaper and now Studio One. Like most (not all) other Novation controllers, the Nocturn uses a piece of Novation software called Automap Server, based on the Mackie HUI protocol. As long as your DAW recognizes HUI, your Novation control hardware will work. You just have to go into the Automap software and activate the VST, AU or RTAS plugins you want the controller to recognize, and in Studio One, assign your device to Automap HUI when adding it as a new Control Surface in External Devices. Works great!
However … what I'm asking about here is using the Nocturn (or other Novation hardware) strictly as a MIDI controller, required to control native Studio One plugins via CC#, which you can do in addition to using it under HUI.
This requires a separate protocol, called Automap MIDI. Here's how you set it up:
https://support.novationmusic.com/hc/en-gb/articles/206863839-What-is-Automap-MIDI-and-how-do-I-use-the-Automap-MIDI-clients-
Once you've done this, you will be able to add your Novation device to External Devices a second time , this time as a keyboard, assigning its in and out ports to Automap MIDI, which will appear in your MIDI list once MDI client has been set up.
If you've gotten this far with your Novation device, you might find it still doesn't work. That's because now you need to create a MIDI map for your device in Studio One. Here's how:
https://music.tutsplus.com/tutorials/setting-up-your-midi-controller-inside-studio-one--audio-16986
The Nocturn can handle as many Control Change numbers (CC#) as there are available in the MIDI CC protocol. And works like a charm, for controlling dedicated S1 instruments, in addition to other features such as S1's console, transport, etc.
So here's my question:
How do I save my CC# assignments for one instrument, e.g., Mai Tai, then reuse the same CC#'s for a second instrument, e.g., Impact? Obviously, I could run the gamut of available CC#'s, assigning a few to each of several instruments in a S1 song, then make reassignments as necessary when I run out of CC#'s. But is there any way to save assignments for each instrument separately, so that I can reuse a CC# with a different instrument in the same session?
In case I'm not being clear, if I assign CC#7 (Volume) to the Master Volume in Presence XT, and then assign the same CC#7 to the Master Volume in Mai Tai, will moving the assigned knob on my Nocturn (or any MIDI controller) move both software controls together, or will just the active one on screen be adjusted? Or is there any way to achieve this.
Hoping this may have been helpful for some, who hadn't got this far as yet, and also that others more knowledgeable than me may be able to answer my specific question (without my having to trudge back to the drawing board). 
Thanks for reading, and hopefully responding.