Hi Tyler, thanks for reading my article! App Shell is an architectural pattern for building Progressive Web Applications where you ship the minimum required resources to load the site. Angular Universal is for speeding up the server-side rendering process. App shell can be implemented without combining with Angular Universal. Please check this link for better explanation https://stackoverflow.com/questions/45278168/angular-2-possible-to-combine-app-shell-together-with-universal-rendering.

If you can provide some samples of what you are trying, may be I can help.