RMX Tools & Brace Layers

I’m trying to find the best practice for superscript characters where the character becomes bolder than the boldest master it references.

I’m attempting to use a brace layer on the outside of my main interpolation range so it will scale using that layer as reference without having to create a new master. This works with RMX Tuner but not RMX Scaler (where I need it most for superscripts)

Here’s the link to a video showing my issue.

Is this something I can fix, or is there a better workflow for generating certain characters outside of the main interpolation space?