Using Typekit fonts in Redactor I need to use a Typekit font in Redactor, but I'm not quite sure if I've done something wrong, or if Redactor's made a breaking change.

I'm enabling the iframe = true parameter in a custom.json redactor config, and then loading Typekit with the initCallback parameter. However, Redactor isn't placing the iframe (as of Craft Pro 2.4.2691) that Typekit uses for selection purposes.

Any ideas? has Redactor recently made a breaking change?

TL;DR: What's the best-practice for using Typekit fonts in Redactor fields as of Craft Pro 2.4.2691?
I would try to add the fonts with the Craft plugins

Control Panel JS
Control Panel CSS