musica ficta with an additional accidental

[Josiah Boothby]

I'd like to write a suggested/editorial accidental above a note that
already has an accidental to the left of the notehead, and would
ideally like the alteration to transpose when the voice is transposed.

Example:

A C-sharp with a suggested natural, transposed down a whole step
should be a B-natural with a suggested flat.

I am able to make this work with tags, but am looking to see if there
is a better way. Should there be a feature request for a command that
inserts an accidental above the note (e.g., cis^\ficta #'natural  [1]
or bes^\natural) without altering the accidental to the left of the
note, but with the ability to be transposed?

Thanks,

Josiah

[1.] Perhaps folks who know old notation better than I could suggest a
more appropriate name for such a command... this is worlds away from
my area expertise.