Trouble generating Bravura Text / submitting to Bravura

Hello,

I am a new member here. Thank you all in advance for being patient with me
as I ramp up.

I have searched the archives already (including the older archives on
Nabble) but haven't found what I'm looking for yet.

This is my situation: I am a volunteer contributor to the Sagittal
microtonal music notation system (http://sagittal.org/). I am working on
submitting both new and updated Sagittal glyphs to Steinberg via an updated
Bravura font. Before I finalize my submission, however, I want to ensure
that the vertical positioning of my glyphs is just right with respect to
staff lines. I am familiar with Bravura Text's ligatures using
combining staff position characters (
https://www.w3.org/2019/03/smufl13/tables/combining-staff-positions.html).
However I am unable to generate new versions of Bravura Text using leading
font editing software such as FontForge and FontLab; even without making
any changes to Bravura Text, exporting or generating the font leads to
invalid files (unable to be installed) which have much larger file sizes
than they should. I am able to export/generate new versions of Bravura just
fine; it is only Bravura Text which I cannot create new versions of.
Bravura does not give the ability to test the combining staff position
ligatures to be able to test my new and updated glyph's vertical
positioning, which is why I need to be able to copy my new and updated
glyphs over from Bravura into Bravura Text.

So questions related to this situation are:
1) Is there a better way (than creating a new version of Bravura Text) to
confirm whether my new and updated glyphs will have the correct vertical
positioning relative to the staff lines? Am I missing something fundamental
about how to contribute to Bravura?
2) If not, has anyone else had this kind of technical trouble generating
new versions of Bravura Text?

On a related note, the ligatures for Bravura Text do not work for me with
the web font versions. The .woff file included in the GitHub
release includes the ligature glyphs, however the lookup tables mapping the
pairs of code points to these ligature glyphs are missing. I thought it
might be as easy as restoring the ligature lookup tables, but my attempts
were inconclusive -- again, because I cannot generate new versions of the
Bravura Text font using the font editing software applications I have
tried, whether through their UI's or their scripting tools. I suspect,
given how elaborate the installation process for Bravura and Bravura Text
is, that something more complex is happening in these fonts that I don't
know enough about yet to account for.

Thank you again for your patience and for any guidance you can provide me.

Best,
Douglas Blumeyer