Advice on keeping Masters to a minimum

I have a typeface with 4 axis: Width, Weight, Slant and Gap (for a stencil-like effect). I’m trying to keep the number of Masters to a minimum.

The following Masters get me all the required Weights and Widths.

Condensed Light
Condensed Bold
Expanded Light
Expanded Bold

Adding two additional masters for the Gap axis gives me a fully variable gap parameter that interacts nicely with all Weights and Widths.

Condensed Bold Gap
Expanded Light Gap

Now I want to add variable Slant. Does this mean I need duplicate all 6 masters? Is there any way this could be optimised so that there are fewer Masters?

Condensed Light Slant
Condensed Bold Slant
Expanded Light Slant
Expanded Bold Slant
Condensed Bold Gap Slant
Expanded Light Gap Slant


Just add one master and see what happens. Then add masters and/or brace layers as needed.