How to adjust spacing between specific glyphs in intermediate layers of a variable font?

Glyphs
1

"I’m working on a variable font using intermediate layers (brace layers) for design interpolation.

I need to adjust the spacing between specific pairs, but since kerning can’t be applied to intermediate layers, I’m stuck. Modifying the sidebearings affects all other combinations, which I want to avoid.

Is there a way to achieve contextual spacing or a workaround for this issue?"

2

you can add custom kerning code that addresses it. It is a bit cumbersome but possible: Variable GPOS — Glyphs Handbook