Diamond noteheads: mensural notation and harmonics mixed up

Dear everyone,

I am making my own music font, and one of the things I’d like to do is to make the attachment points for stems on the white mensural noteheads (E933, E937, E93C and E93D) centered, like they are in mensural notation. This would be useful for renaissance edition incipits for example. I have figured out how to edit a JSON file, so I know how to make the stems attach correctly.

I now found out that Dorico uses the glyph E93C for artificial harmonics, or at least for note values of a half note or smaller. Longer note artificial harmonics are taken from the normal diamond noteheads, E0D7 and E0D8. If I change the attachment point of stems for E93C to match renaissance notation, then I will have a problem with artificial harmonics.

I have thought of centering the stems on E0D9, not used for harmonics, and incorporating it in an otherwise “white mensural” notehead set. And then for a notehead set of diamond notes (I recently needed this when editing a new piece) do the oppositie; have all diamond notes from the range of E0D7–E0DB, and use the one mensural notehead for the half note.

This is a possible workaround, but I don’t understand why it is necessary. Why is that one mensural notehead used for artificial harmonics, when the same symbol is also in the range of normal diamond noteheads?

all the best,

Sorry, my question was waaay to long. To put it simply; why is a white mensural notehead (E93C) used for artificial harmonics, and not a glyph from the diamond noteheads range?

Thanks for your help,