I assume the guest link is the version of online view to an invoice/quote and layout should be similar to the PDF view expect some printed information like footer. It is worth to consider to add the quick button in Option for the guest link as “View Online”. It can help to save the time for the biller to preview the invoice content before send and also help the developer to adjust the CSS using the Inspector. Please consider it.
By the way, how I can duplicate the PDF template to the public? I tried to copy the template from pdf to public folder but no luck.