Fair play, that is awesome, and just what I wanted.

I do have a minor constructive criticism, as someone that does not use Apple, I found the '+' to actually select a Google Font to be far from intuitive. I was looking for a big button in the bottom right with 'Select' (or some other label).

Other than that, bookmarked, kettle on and fired up to get my fonts optimised. Thank you.

I was about to make that command. it needs to be a primary button with text.