Using alternate layers in interpolation

What am I doing wrong?

I have a glyphs file with two masters defined, Regular and Bold.
The /Q/ has four layers:

  1. Regular, with tail that goes inside the counter. (master)
  2. Bold, with tail that goes inside the counter, compatible with 1). (master)
  3. Bold [100], a copy of 2) but with tail that is only outside the counter.
  4. Regular [100], a copy of 1) but with tail that is only outside the counter, compatible with 3).
    Shouldn’t any preview instances with weight above 100 work from 3)/4)? None right now are showing the cropped tail.

The preview doe not seem to respect the extra layers. I will fix this.

Try to generate an instance.

Ah, it does work in generated fonts.

I look forward to having the preview work. On a related topic, is there a way to check compatibility of these extra layers built into the app?

I did fix that. But it will only work for paths in that glyph. If there are components that have an alternate interpolation it will show the regular shape.