SFZ: Channels of the Instruments in the Mixer and Change Instrument Text

I was trying to add more channels to various instruments in the mixer, as I'm using the SFZ "Virtual Playing Orchestra" by Paul Battersby. Some instruments in this SFZ have quite a few types of sounds (Ex. Strings have 8 different sounds and French Horn has 10) and each one needs a channel inside an instrument in the mixer. However, the default number of channels in MuseScore is 3 for Strings and 1 for French Horn.
I don't want to play around with instruments.xml as I know nothing about code (in case there's code in there), and even if I did, I don't know if that's a secure thing to do while having an existing score instead of an empty score.

I found that the "Change Instrument" text adds more channels into the same instrument in the mixer (depending on what instrument you change to), thus having the possibility to use the rest of the sounds of the SFZ. But even if I did that, if I happened to want to go back to an articulation or sound used before putting the "Change Instrument" text, I would have to create another "Change Instrument" text and edit the sounds again, as if I were creating another instrument instead of using the previously made one (and that could end in a really long list instead of a simple N-item list).

So there's no option of going back to a previously used instrument (as far as I know) and I'm not sure about modifying system files.

Then I found this node about a user having a similar problem:
Instrument change - back to primary instrument

Has there been any advance about this after these three years?
And... Any suggestion?

(PD: Excuse my English, feedback about this is welcome as well)