doesn't the fontmake CLI already allow you to make instance UFOs and select specific named instances? Maybe we could simply add an option to instantiate at some arbitrary location..

i worry that we may then have to support multiple ways to accomplish the same thing, that's all

That does make sense. I was seeing instantiator as a self-contained bit of code, but of course within fontmake it can do almost all of this.

I actually wanted to move that module out of fontmake (which I see just as the command line front-end) to ufo2ft (which is a library doing most of the building logic), but never got around doing that.

Could we make it a separate project altogether? That way if we ever need to replace the instantiator with a different implementation it's all nicely compartmentalised...

yeah probably better that way