How do I further optimize delivery of a single minified CSS file?

Answer 1

Minification would be the biggest optimization. Other than that, it really depends on the structure of your website or application. If you only need certain styles when a user goes on a particular page that is not commonly visited, say an administration page, you might want to load the CSS file when the user visits that page as to save other users on the website from having to load an unnecessary file.

Generally, the amount of time to load a minified CSS file is negligible.