Different character sets on different masters?

Would it be possible (in some way) to have different character sets (with automatic features that mirrors the character sets) on each master within one document? Maybe not in the normal view, but when exporting or something? Maybe a check box, like “don’t export this glyph on this specific instance”.

For instance, one master is the ”Text” version, with both lining and old style figures while the other master is the ”Display” version with only lining numerals, and the old style numeral slots are empty.

There are custom parameters for this. Remove Glyphs and Keep Glyphs and Rename Glyphs, automatic features should update automatically, but you can force it with the Update Features parameter. And you can use Replace Feature for inserting your own code. And so on.

Will it swap the kerning as well ? I have a font with a double storey a and the single one as .ss01. If I swap them at export, will the kerning also be swapped ?

Group kerning: The glyphs keep their kerning groups. They will share the group kerning if they share the groups.

Exceptions: The renaming of exceptions should also be done in the kerning. Please report if you find anything weird.

Renamed glyphs will keep their kerning.

How about a (master or instance level) custom parameter “Remove empty glyphs”:

One could auto-detect a layer as “empty” or “non-existing” if it doesn’t have any paths but other layers of the glyph do (so as not to catch glyphs like space). Any glyph-instance that uses a “non-existing” layer would be removed.