Workflow suggestion for testing out adjustments across a group of glyphs?

I have a larger group of glyphs that I want to make changes to (e.g., adjusting stem widths slightly across all the lowercase glyphs) then compare against the previous version to see which I prefer.

When I’ve been making variants of a single glyph, I’ve just been using different glyph layers to test between.

With a larger group, I see two primary options:

  1. continue using the glyph layers, though it looks like I’d need to go through one by one to make the copy back as master.
  2. create copies of the glyphs (as .001, for example) and use batch renames and export checkboxes to determine which is in use (or go crazy with a new instance and some filter glyph removal and renaming).

Or, is there some workflow path that I’m missing? Suggestions appreciated.

If I go with the glyph layer path, I’ll probably create a script to do a rename to something more symbolic. From the font view, I did create a glyph layer copy of the selected glyphs for each master, so I’d have copies of the current state before making changes.

Is there a way from scripting to make a specific layer a master?

What I do in cases like this is create a second set of glyphs and a dummy ssXX feature and activate/deactivate it via the features menu. This also works with a test export of the OTF in InDesign.

If you want to do that, this script converts layers into separate ssXX glyphs:
https://github.com/mekkablue/Glyphs-Scripts/blob/master/Stylistic%20Sets/Create%20ssX X%20from%20layer.py

In case your glyph variations are point-compatible: Have you tried the background interpolation in the Transformations filter?

You can turn a layer into a master via the gearbox menu in the layers section of the palette.

Make the changes in a new font with a different name. Then compare the two fonts letter by letter with Glyphproofer: https://github.com/houseind/robothon/tree/master/GlyphProofer

This is certainly possible. I could look into it if you like.
I've not looked into that, before. It's unclear how that would work. Are you talking about being in "Edit Background" mode and then applying the Transformation filter? I did see the Background tab in the Transformation filter with a percentage slider. I'll have to experiment (unless there's some documentation somewhere on it that I've just overlooked?).

The ssXX variants/feature was one of the thoughts I was considering, too. Thanks, Eric.

That was a third option: work on a copy of the font, perhaps with revision control. In this case, I'm looking at how some subtle overall adjustments change the color across a range of glyphs. When I'm spending time comparing details, perhaps GlyphProofer will be something to play with; I'll have to install the dependencies and check it out. Thanks, though I knew that. I was looking for a way to have the same named layer across selected glyphs be made master. That's why I was curious about being able to do so from a script. It might be useful for some scripting/workflow combinations.

Thanks for the suggestions.