Add a Custom Parameter to each master of your font.
It goes by the name StemRhythm
And it takes some parameters:
105;86;240;92%;88%
———
# Left and right side bearing
105;86;240;92%;88%
————
# Stem width
105;86;240;92%;88%
————
# Size of counter for one bowl glyphs
105;86;240;92%;88%
———
# Size of counter for 2 bowl glyphs
# *Optional*
105;86;240;92%;88%
———
# Size of counter for 3 bowl glyphs
# *Optional*
# 4 counter glyphs: and so forth …
If you like it, feel free to: