More than two axes for interpolation

Is there any way of adding extra axes (more than two) for interpolation. I noticed in the Masters window under Weight and Width, there’s an unaccessible “Custom” field?

I’m working on that.

Allowing us to rename the existing fields would be cool, too. Right now I’m using the width axis for an optical size axis.

Expanded interpolation capabilities and related interface improvements seem like something that would be good to have in Glyphs 2.0. Lately I’ve been thinking that the Font Info window might be better off as a full-screen tab. In addition to providing more space to arrange all font data, and making the overall application design more consistent, this would be great for managing instances on more than one axis. A full-screen interpolation space showing masters, active, and inactive instances in different colors could be pretty useful.