Customizeable default position for palette custom symbols

Context: a custom symbols, say an SVG, is added to a palette. When the symbol is added to an element, say a note, it is always placed at the (0,0) position with respect to the note (or element).

But often the symbol has a specific default placement; for instance, these ornaments used in French viole de gambe music are consistently placed one to the left and the other above the note:

Another example could be the Bach's appoggiatura symbol discussed in this post .

Request: a way to specify a default (x,y) placement, in spaces, of a symbol added to a palette by the user. As a UI, there could be two spin boxes added to the "Properties" of a palette symbol where the user could enter specific default displacements after adding the symbol itself.

Thanks,

M.