Where do you want your text to appear? Your problem reminded me of this:
Could it be of help in your case?
Gabriel
EDIT: it could be even simpler than that: from version 4060, Cantabile should support the modulus operation, so you could use something like (assuming CC #32 on channel 16 is used):
After a few test, and after realizing how stupid I was assuming you needed the modulus operation ,
I think this could work (using cc #33 on midi channel 1)
However, are you sure that you are able to reach A# and B with this command?
The highest value you can get from a CC is 127, which would give you an index of 10 into the string (and there are 12 entries). That’s why I thought your initial choice of 7 was ok.