vertically aligning stave text or adding figured bass or Chord symbols?

Hi all,

I'm writing a plugin for musescore v2 that summarizes the vertical sounds (chords) throughout the score, and prints the result on the score.

The idea is to write some string representation of the sounding chord (could be proper chord symbol, or figured bass like notation - let's assume some arbitrary string) whenever there is some change in some voice on some stave (new note sounding, or previously sounding note silenced by a rest) that essentially changes the previously sounding chord.

Obviously, I would like the output to be horizontally aligned to reflect exactly where the change occurs in time. At the same time, I would like to print my plugin output below the last stave of the score, or alternatively, above the first stave, and in such a way that all chord symbols appear at a fixed vertical position.

How can I do this?

Currently, I am using stave text. This is my code:

function writeChordStringRepresentationToScore(cursor, chordStringRepresentation){
//get a note with a tick where the chord changes.
var targetNote = chordStringRepresentation.targetNote;
//init the cursor
cursor.track = targetNote.track;
cursor.rewind(0);
do {
//if our cursor is positioned to point to our targetNote,
if (cursor.element && cursor.element === targetNote.parent) {
//create staff text
var staffText = newElement(Element.STAFF_TEXT);
//attempt to position the text below the last staff by adding 10 space for each staff
staffText.pos.y = (curScore.nstaves - cursor.staffIdx)* 10;
//actually set the text and add it to the score.
staffText.text = chordStringRepresentation.text;
cursor.add(staffText);
break;
}
} while (cursor.next());
}

Basically, the chordStringRepresentation argument contains both the textstring (.text) I want to print, as well as some note (.targetNote) that is at the tick where the chord changes. I use the targetNote to position the cursor (in order to achieve the right horizontal alignment) and then I add stave text, with an extra vertical offset of 10 for each stave between the stave where the targetNote sits and the last stave

The problems with this approach are that
1) Assumming 10 offset for each stave is a too rough approximation, totally disregarding the actual height used by a stave. I don't know how to find out how much height the staff actually uses. I cannot simply write stave text on only the last stave either, since the last stave might not have a note or rest at the actual tick where the chord changes, which I believe I need to achieve the horizontal alignment I need.

2) Even if the per stave vertical offset would be accurate, the vertical placement of the text depends on the vertical position of the targetNote. That seems to be just how stafftext works, and I don't know if and how I can change that.

I was thinking there should be a better way to achieve what I want, perhaps even use actual features like "chord symbols" or "figured bass" to print my output too, but I just can't figure out how to control these features from within my plugin code.

Can anybody please point me to some code that shows how I can either position my stave text, or how I can add chord symbols or figured bass text?