Spacing formulas across Multiple Master

Is it possible to have different spacing formula in different masters?

The Light q glyph has a right side bearing of “=n+1”
The Bold q glyph has a right side bearing of “=n+4”

However Glyphs moans at this and throws up an exclamation warning.

Hi Jeremy,
You can use “==n+1” for light master and “=n+4” for bold.

does the == relate to first master/second master
do you use === for a third one and ==== for 4 master?

You can use the “==” in the first or second master.
I think that more than == isn’t possible

Thanks Eduardo

The double equal sign means that it is stored in that particular layer instead of the glyph. So you can add it in each layer/master.

Great. Obviously that applies to any formula.