"correcting" multi-axis interpolation in specific glyphs in variable fonts

Hi so I’m trying to get a variable font with three axes to interpolate correctly when multiple axes interact with one another. I’m trying to have one axis for width and another for “checkered-ness” However these interact in a way that is difficult to predict/control.

The screenshot above shows that the separate axes “behave properly” when separate and then how they don’t behave “correctly” when I try the font out in Font Gauntlet. I started with E which in this font doesn’t have curves, and that works as expected but I’m wondering if this is possible with the curves and how I could either fix or re-examine how I think about this issue.

(sorry I can only put one piece of media in a post, below are screenshots from glyphs showing the separate axes work as expected)

In designs I’ve made with complex interacting axes, I’ve found I needed an annoyingly large number of masters to “cover the corners” of the design space.
Post your existing master locations and perhaps somebody can offer more efficient solutions.

I have the 4 masters and 3 axes (checkered-ness, angled-ness, and width). I have the masters set up to be

  1. 0 for all axes ({0,0,0})
  2. 500 for checkered-ness ({500,0,0})
  3. 500 for angled-ness({0,500,0})
  4. 500 for width({0,0,500})

I believe what I need is intermediate/brace layers, so that I don’t need to redraw every glyph in the “corrective” locations. I think the part I don’t understand is how to take intermediate/bracket layers for different locations on a specific glyph and get them to export properly.

I can create an intermediate layer for a specific glyph, and then I don’t understand the “virtual masters” section of the page on intermediate layers