Initial loading of the site takes a relatively long time. Investigate the following, and apply basic improvements or add separate issues for bigger changes:
What's taking the most time and ways to reduce them
Building the project with Polymer CLI and how to streamline it
Service worker and how to cache components
If there's a way to batch load components, so separate requests don't need to be made (referenced in Google IO video a few years ago)
Initial loading of the site takes a relatively long time. Investigate the following, and apply basic improvements or add separate issues for bigger changes: